Or, if you already use uBlock Origin and would rather use its performant, customizable, extensible filtering capabilities instead of adding (and trusting!) yet another addon, just check the "EasyList Cookie" list in your Filter Lists :) .
1. Never seen a cookie div.
2. Never been bitten by incorrect / false-positivey / over-zealous rules.
Everything else being equal, more options is good, but I don't see any reason to switch from Easylist Cookies, which I know is well-maintained, benefits from the Easylist umbrella, and has lots of users (since it's offered by default in uBlock Origin).
EDIT: browser makers are understandably cautious about it, even with a closed ecosystem it's already hard enough for them to avoid half their users getting pushed into installing dubious/malware addons within three hours of browsing, and their resources are limited. So, they default to closed-ness "for the masses", but there's a knob. I don't find this unreasonable.
I think more restrictions should be put on extensions but it's always hard to balance between accesible developers tools to people who know what they're doing and somebdoy writing down the instructions how to circumvent it to lure the user to install a malicious extension in developer mode.