Big companies are not to be trusted. That has never changed and probably never will. So yes, this is definitely a loophole that is probably exploited a lot.
And as is so often the case - as annoying as it is - anyone with enough knowledge bypasses all this crap.
In this particular case: an add-on that automatically accepts all cookies and one that automatically deletes all cookies after closing the tab or browser, excluding a defined list of exceptions and specific rules defined therein. I don’t need to mention adblockers and DNS obfuscators; everyone with half a brain uses them anyway. The same applies to mobile browsers. Firefox is currently still one of the last remaining defenders against the Chrome epidemic (it has unfortunately lost in the iPhone world due to technical K.O. ).
AFAIK they said within this year.
But I expect that most addons won’t work out-of-the-box on release day. Many of them will be either conceptionally incompatible or too resource intensive for most Android phones, which makes Android kill the app. The Devs said they created a framework to fix this issue, which extension devs can use to adapt their extensions for mobile browsers.
Don’t expect every single addon to work right away. It’ll take time - probably a year or so - until most relevant extensions support mobile Firefox.