Collectables are an awesome new spin on the turn-in system for both crafters and gatherers. We've done a fair amount of both (miner and gsm), so here a decent explanation of both.
Collectables serve two major purposes.
1) They serve as a convenient new way to get experience.
2) They are the new turn-in system (replacing stuff like gather 99 HQ umbral rocks or craft 3 HQ Calibrated Rose Gold Cogs) for getting Scrips. Scrips buy you a set of decent entry level gear, some special mats/temporary buff items, and most importantly: Your master books. For gatherers they purchase tokens which unlock the ability to see the new 1 star nodes in certain zones.
The entire collectable system for gatherers is the best ever. First off: You don't need hours of mindless grinding or a billion leve allowances to level anymore. Collectable nodes can net you an insane amount of exp in a short amount of time. If you do leves between hitting collectable nodes, you can level very quickly!
So how do they work? Basically you look at your timers menu and rowena tells you what she's looking for. Unlike other turn-ins that ask for an item and give 2x exp for HQ, or turn-ins that ONLY take HQ, this time there are tiers of turn-ins. An item can either be level 0, 1, 2, or 3 based on how much collectability it has. If you don't make it up to the minimum amount of collectability, the item is completely useless (level 0). Levels 1, 2, and 3 give a different amount of experience and Scrips based on how much collectability you generated.
As an example, the level 50 requested item is usually Yellow Copper Ore with a minimum of 240 collectability. This means you'll get nothing for yellow copper ore with less than 240 collectability, the base 60k exp for each ore between 240-399, 66k for each between 400-449, and 72k for each ore over 450.
Now how do you get collectability? It's a fun minigame of its own! So you approach your 12 am/pm node (for yellow copper ore) and it has 8 (?) slots. Figure out which slot your item is in, and once it's revealed MAKE SURE YOU HAVE YOUR COLLECTOR'S GLOVE BUFF ACTIVE then try to gather it. Now a new menu should pop up! Similar to when crafting, you have a limited number of actions to raise the item to as high of a quality (collectability) as you want, while not breaking it, before gathering the items. In this case, you're balancing your GP, the item's Wear, the number of gathering attempts you have left, and the total collectability of the item.
Basically, you'll use your Appraisal skills to raise the rarity up as much as you can, then gather as many ore as you can. In more detail: Each appraisal action generates rarity based on how much perception you have, while raising the Wear on the item, and consuming a gathering attempt. If the wear exceeds the maximum (e.g. 35/30) your gathering chance drops to 10% and cannot be raised by abilities. Basically, you broke it.
The bestest part of this (IMO) is that you can calculate what rotation you need to do in advance! The fact that most of it is non-stochastic is AMAZING. As an example: If last time you were at the yellow copper ore node, you found that Methodical Appraisal (essentially your Basic Touch skill) generated 96 rarity, then you'd know that if you used Methodical Appraisal, followed by Discerning Eye (1.5x next appraisal action) -> Methodical Appraisal, you'd generate 96 + (96 x 1.5) rarity! That happens to add up to 240 collectability :D.
What that means is if you know you can generate 96 on a regular hit, then you know that with two hits and 200 GP, you can generate enough rarity without going over the Wear maximum. This kind of thing is awesome because you only get 6 attempts on a node. If you use 1 attempt to reveal and 2 to get the collectability up, then you can gather 3 collectable ore over the minimum and get 180k experience off of a single node!
As you level you get new awesome skills (like Single Mind) that let you come up with new ways of maximizing your exp or scrips per node. Note: Most often, MORE items > higher quality items. If you can get 3 level 1 items, its usually better than 2 level 2 items based on how the exp scaling works. So practice and you can get that.
TL;DR For gathering, collectability is a new minigame that replaces turn-ins to help you level quickly and get your fancy books and gear. It is less painfully dependent on RNG than trying to get HQ!
For crafting, all of the systems for quality are already in place. There's not as much new stuff to learn. In short: Collectability turn-ins for crafters kind of suck, but can also be nice for newer players.
Collectable turn-ins don't generate ANYWHERE near as much exp as levequests for crafters (unlike gatherers where collectables was king). Additionally, the amount of scrips you get is severely limited and the mats for the crafts are expensive. As an example: it can take 15-20 level 3 turn-ins (that would have sold on the MB for 500k each at the time) to get enough crafting Scrips to get a single master book. Note: Crafting and Gathering Scrips are totally independent. Sadly. You can see how this can get pricy quickly! Unlike gatherers who can just hit up a node once every 40 minutes, crafters have to use a LOT of expensive new mats to craft items just to turn them in.
So how does collectability work for crafters? Much like gatherers, BEFORE YOU START THE CRAFT you must activate the collector's ability which declares your intent to craft for rarity, not HQ. I've accidentally made 100% HQ turn-ins before that were useless and I ended up having to sell them (it took a long time to gather those mats by hand QQ). Once you start the craft, proceed just like any other craft. This time though: There won't be a % chance of HQ. Instead whatever quality your item is at when you finish the craft is the amount of rarity it will have.
As an example: My level 59 GSM turn-in is a Citrine Choker of Casting. Level 1 minimum is 3500 collectability. Level 1: 3500-4899, Level 2: 4899-6299, Level 3: 6300+. What's important to note here is that a Citrine Choker has a maximum quality of 7339. That mean's you'd need 7339 quality to get 100% HQ chance. Of that 7339 possible, you only need 3500 to get credit for this collectable turn-in. Additionally, every point of quality over 6300 is literally meaningless. Usually, though, if you can get to level 3 you'll probably be at 100% anyway, because you're probably well-geared and have a rotation that ends on a big byergot's blessing regardless.
In the old system, you needed to HQ 3 absurdly difficult and expensive items. Even if those crafts went exceptionally well, you'd often only be able to get to 50% chance of HQ just to watch it NQ with mats that cost 100k each and fail. In the new system, there's no awful RNG at the end of your crafts! However much quality you generated is how much collectability your item will have, and that DIRECTLY DETERMINES the level of turn-in you achieved. You can make it to less than 50% of the total possible quality (which usually amounts to like 10% chance to HQ) and STILL GET CREDIT. My level 59 turn-in is starred today, so I'd get 26 Scrips for a choker with 3500 quality (collectability). If I got 100% of the possible quality, it'd only be worth 31 Scrips.
When you're mass producing these to unlock your master book, every Scrip counts, so 5 more is a lot. If you're new to crafting, and didn't have 4 star crafting gear when HW dropped and tons of practice HQing difficult crafts, it can be really hard to get that much quality on a craft. Thus: The new system rewards experienced and well equipped players, while reducing the dependency on RNG, and at the same time makes it easier for newer crafters to get their Scrip gear/books and start learning!
TL;DR: For crafting, Collectables can get pricy, and aren't nearly as efficient for leveling as levequests. However, because they aren't as heavily dependent on RNG and have tiers of accepted quality as opposed to a binary HQ or NQ state, it's a great system for newer players! Hope u enjoy it !