Not sure what the specific benefits of SteamOS are. It’s forked from Arch, I don’t know what Valve changes. Maybe slightly better hardware support for Steam Deck? I run Steam on Fedora on my desktop and have no issues.
I work as a sysadmin during the day, fixing PCs and stuff, and I really don't want to continue doing that after I get home - I just want to pick up my controller, put my feet up and get straight to gaming without having to worry about updates and other PC annoyances.
The best part is, if on the rate ocassion an update breaks something,I can easily boot straight to the previous image from the boot menu, without needing to run any commands or do anything special post-boot. And with Bazzite (and other uBlue distros), I can go back upto 90 days worth of images (3 previous local images + older images pulled from the cloud). I can also pin a known "good" image so it'll always be available in the boot menu. Essentially I get a rock solid unbreakable system, which is great because after a hard day's work, I really don't have the patience to deal with any PC issues at home.
I should have clarified that I meant the performance benefit of SteamOS over Bazzite specifically.
I love it, but there's probably not a whole bunch of reason to run it on things in other form factors.
The whole OS is made for controllers, no need for a mouse/kb for anything.