To me, Firefox has way better dev tools than Chrome. I don't even mention Safari here - who can stand their horrible dev tools? Firefox has a fantastic add on marketplace which competes with Chrome's. Firefox without too many addons actually do not drain battery life on MacOS. Firefox has "native" profile management with real separation of cookies. JS benchmarks provide no value to me, since I try to avoid heavy-JS web apps anyway.

I don't know. As a dev and user, Firefox wins on every single aspect for me. I understand that every user is different. But I'm glad it exists.