While SteamOS is Arch based, i don't think they really use it the Arch way. It's run as an image based immutable OS, so they control the packages and not run at the bleeding edge.
You might run into problems more likely than SteamOS will.
Although i didnt't have problems gaming on Arch, it's not the same
LTS distros and extremely delayed packages can give you problems for sure, the components used for gaming are very fast moving pieces fixing latest issues constantly.