Why users have to use this when there is "Delete cookies and site data when Firefox is closed?"

Firefox can block, allow, allow session per website in Settings, Privacy & Security, Manage Exceptions…

Also nukes cookies responsible for keeping the EU commission cookie confirmation info, this can break websites like YouTube which won't let you play any videos until they get that confirmation.
So if your AdBlocker blocks that EU commission confirmation pop-up window, while Cookie AutoDelete also removes cookies with existing confirmation info in them, you won't even know why the site doesn't work. Until this addon gains an option to ignore those EU commission cookies, 3 stars is all i can give.

The New York Times has Defeated this software.

Seems to miss a lot of cookies and site data. Judging by the devs response below this happens with strict mode/cross-site cookie protection / all Third-party cookies enabled.

Does not work any where near as well as it used to when I first got it. Now it leaves MANY cookies behind in Firefox 95.0.2 Standard mode

The lack of synchronization between devices can be a nuisance.

For deleting cookies this is superb. But as it's matured it has become incredibly complex with so many options but too few explanations as to how to master the add-on. Being a bit of a privacy geek, I want to reject all cookies that track and exploit my details but have an EASY option to make the site remember that I've rejected everything not essential. Instead I have to constantly keep rejecting everything. It's always back to square one As per usual every individual uses an individual phrase when searching for the answer. If it is in FAQs, I don't have the patience to read a War & Peace to find what seems an obvious request.

Ok

Straightforward to set up and does its job at forgetting cookies.

With the new forced welcome page/changelog, I have to disable auto-update because I cannot stand add-ons opening tabs without warning and stealing focus -- especially when these updates bring little to no added benefit.