Also, if you frequently use cross platform software on multiple platforms, it’s possible consistency within the app is more important than consistently with the OS.
Granted neither of these are deal breakers for me. I don't use Firefox b/c of pretty context menus.
Last time I used Chrome they pretty much reimplemented everything from buttons to modal sheets.
But also ended up completely moving out of most "native" tools for a reason or another (from TextMate to VSCode, Mail to Gmail tab, FaceTime to Skype/Meet etc.). At this point deep platform integration looks more like exceptions than the norm, for the better or worse. There are things that I kind of hate in a lot of Apple product (Safari included), which make Firefox's approach a decent tradeoff.