I'm guessing the 3-band was added way earlier when they accepted more code or as a test for the extensions in general, but I'm no OBS developer, I cannot really

I'm guessing the 3-band was added way earlier when they accepted more code or as a test for the extensions in general, but I'm no OBS developer, I cannot really answer to that. Pipewire effects for equalizer and so much more already exists (personally I use Easy Effects for that), and the people I know using OBS are kind of stuck with Windows because of other reasons. Also, it's nice to have everything you need in one package. But, you're the author after all, you decide what you want to do :)