This runs SteamOS and is an officially supported platform that, if it has legs, will be something developers may want to target as a platform and make sure their games work a la Steam Deck verification.
There's also potential for community fixes for older games with issues. And easier troubleshooting cause you can just look up "fix for X game Steam Machine", or "does X game work on Steam Machine"
There are advantages to this over something generic, or building your own machine.