Also because of their no-DRM policy which forces games publishers to remove any DRM from their titles before they can sell them there, older Windows-only AAA games sold there don't have the $&/"%*$# DRM that often makes them almost impossible to run under Wine or Proton.

I mean, you still have games from GOG that won't run under Wine no matter what you do, but at least you don't have the situation like you have with Steam were the game you bought won't run in Linux yet a downloaded pirate version of it runs just fine.