+1 ,but you can always add external games to Steam. I tried it once, and it worked. However, I prefer GOG over Steam because of its DRM-free policy and also prefer clean Wine over Proton, as I can report bugs directly to Wine bugtracker. I have some Steam games installed on Wine. Yes, I had to first install Steam inside Wine prefix and only after that install the games. Additionally, there is always pirated software, which I won't add to Steam.