Only missing feature compared to SteamOS 3.6 is HDR, we're waiting for Fedora to land it in stable rather than port all of that from SteamOS.
And then of course there's a ton of features we add that SteamOS doesn't have. We build from stable Fedora and keep our patches minimal so the intent is for Bazzite to be as stable.
I'm way too lazy to jump through the hoops of reinstalling games, but when I get a less tiny SSD and have to jump through hoops anyways, it does seem like it's worth trying.
I've been looking for an immutable, gaming ready distribution for a while and taking a closer look at bazzite it just might fit the bill perfectly! I don't even mean only for the deck necessarily, strongly considering replacing the Nobara install on my main PC and see how well it handles my NVIDIA card 🤔
Why immutable? I've seen this sentiment before but I'm not really sure what the benefits truly are other than easily upgrading the OS and distro agnostic applications, but even that's kind of not really a benefit IMO.
If you have the time and willingness to fix your linux install then immutable is not for you. If you have the need to have a device that you can't wreck by accident, then it might be a good choice.
I found the suse immutable distro a bit too much learning over just sticking to arch, but bazzite and the other fedora based immutable distros have been great for not having a shit time every day when my mom group calls me with the ISP tech support and when asked what her operating system is she says Firefox.
I haven't touched my parent's computers since installing kinoite and it stays up to date on its own without breaking anything and I love it. I have bazzite on my laptop and steam deck. I can install so far anything I have wanted with little to no issues and it persists after updating which steamos can't do.
I still have a few other computers running dietpi on the sbc's, arch on one server and nixos on the other for testing misc stuff but since you no longer need to self compile bleeding edge versions of everything to get games to run or have your wifi card show up, why would I? I did my time back in the days of installing various distros on the family win98 and XP computers and the PowerPC macs when the school district upgraded and gave them out.
I should probably add that I haven't really daily driven an immutable OS yet, so this isn't from extensive experience or anything.
I'm big on trying to keep my system separate from userspace and also making my environment as reproducible as possible. I enjoy using Ansible and Nix-based environments to get some degree of that in more traditional distros, an immutable system would give me an extra layer of predictability I appreciate. I'm also a developer, so I enjoy having containerized development environments, which lends itself well to a stable base I don't have to worry about. Plus, like you mentioned, updates being more solid and reliable, often reversible, is always appreciated.
That all said, I totally get that for your average user none of that may mean much and that's fair game.
If I ever get a Steam Deck, I'll definitely be willing to try Bazzite. Hell, when I update my laptop to something with a lot better hardware, I'll be sure to try this in a virtual machine and try it with Waydroid.