I don't think calling gaming on linux "possible" gives it the justice it deserves, with the arrival of the Steam Deck and all the improvements Valve contributed to the upstream. The experience is practically _seamless_.
I agree though that linux _on desktop_ is pretty janky, or at least it always was for me, having tried daily driving numerous distros.
IF you buy through Steam. IF you have an AMD GPU. IF by seamless you mean that regardless of the aforementioned BIG assumptions you still have to go and play with winetricks or whatever to get some stuff working and it can take you hours of tinkering.
Okay, that's fair enough. Though even if you have a game that you bought outside of Steam, you can add it as a non-Steam game to benefit from the compatibility layer and all the bells and whistles.
I agree though that linux _on desktop_ is pretty janky, or at least it always was for me, having tried daily driving numerous distros.