For sure, but it’s not really the same functionality. You can play your games, but you can’t buy or redeem any others from Heroic or Lutris.
It has a store page, basically an embedded web browser, I redeem free epic games through it, don’t know about GOG but I’d imagine it works the same.
The heroic launcher supports GOG.
True but paying customers can expect that CD Project to that by themselves from the cut they take from games on GOG and the insane amounts of Cyberpunk money they earned. Randy Pitchford claims that “Steam does very little to earn the massive cut they take and continues its effective monopoly” and that “very little” includes making clients for three operating systems, a VR platform, a handheld, and a whole operating system.