I think that comes with risks, they will need to do a lot of work to manage expectations which is likely to be an unending uphill battle getting users to read and absorb any notice you put in front of them. If there's ever an official version of SteamOS that installs as broadly as most other linux distros along with a general/minimally trained audience, they can't do Deck certified on how well each game works on your system, and I can see challenges for "why does this game I bought on the steam store not work on my steam system?" especially if it's the hot new multiplayer game that targets windows with windows-only anticheat.

PC does have a fair amount of users that want it to operate in a console-like way when it comes to usability, the moment you tell them to fiddle with a runtime or experiment with the command line variables you lose them. That's to say nothing about handling stuff that lives outside steam, because PC gaming shouldn't equal Valve. The Deck is a nice manageable subset to deal with and fairly small enthusiast audience

I assume jjcm was talking about Valve shipping dedicated hardware, e.g. a Valve-branded gaming laptop which boots into SteamOS. That could help them achieve the same level of "Just Works" that Apple gets with macOS.