I think it’s more important that it gives Valve a method of avoiding being shoehorned into a “Windows only world”. The Steam Deck is largely why Linux has pushed past 2% market share on the Steam Hardware Survey consistently now. Holo, which is the codename for SteamOS on the Deck, makes up over half of Steam on Linux.
Don’t get me wrong. I’m not dillusional. Windows is still far and away the majority platform and will be for some time. However, there is a real, functional choice now that didn’t exist a few years ago.