I would disagree, as someone who have a Steam Deck and has a desktop connected to the TV for couch gaming it is amazing.

However most distros still install Grub, and (although not their fault) have a crusty UEFI boot sequence making that startup sequence worse than it needs to be.

Steam also haven't officially released SteamOS 3, so unless you are going to do a bit of modification, it won't quite be as slick.

On the other hand, even with all that it is vastly better than the Windows experience.