For add-ons, mostly. I use Tree-Style Tabs and can't live without it at this point.

I can't find any reason to use an alternative browser

Honestly, when I got my first Ubuntu install disk and got everything up and running, it was the default browser. I just never looked back.

Cause it's the Red Panda browser, cuddly creatures🥰

Because I never particularly liked the alternatives.

Trust. I think it has been earned - so far. NCSA Mosaic was my second browser, and while I've experimented with all the major browsers and many not-so-major contenders over the interim couple of decades, Firefox has been a constant for me ever since it was first spawned off of Mozilla. I still believe the Firefox team when they say things, and so far that has worked out just fine.

When someone built a form that for some reasons doesn’t work with Safari. Or when watching streaming sites with pop ups (FF full screen is really nice in the recent update).

I’d use it more, but I rely on iCloud password management built into safari across my family’s devices and handoff/tab groups to manage tabs across them.

Ctrl+Tab cycles to previous active tab and is actually useful.

Vivaldi is my main browser of choice but Firefox is my backup. I'm logged into both and have sync enabled and have them installed on Linux and my Android.

If a site doesn't work on Vivaldi, I'll try it on FF.

because i'm a furry