I'm using it, if site breaks I usually check which calls it makes on extension UI and lower protection for that API (if it makes sense).
It is suggested by FSF, but not sure why it is not more popular
that is what tor browser is recommending, but they refuse to bundle any ad blocker for different reasons which make sense. but I can't browse with ads, I need uBlockOrigin...
so my thoughts are, if you install any extension you become more unique among tor browser users, and you have same uniqueness for all pages/tabs you load.
what if you appear unique every time you load any page in any tab?