some APIs just aren’t available… i’m not sure about web bluetooth for example, but when i had a play with that a while back (because it was the easiest way to connect to a bluetooth device to hack around), i wrote some control software that was chromium only because firefox didn’t support that API

same goes for some of the crypto APIs

and when firefox blocked cross-origin cookies and a bunch of SSO solutions stopped working… they weren’t garbage, they just were built on technologies that other peoples abused and were later deemed insecure - but not for their use-case

it’s acceptable to write software that doesn’t support firefox if it’s for a good reason