I like GoG for the idea of getting games DRM free. I buy from them when I can.
But there’s some key features of Steam GoG just can’t compete with:
multiplayer infrastructure
gifts and other interactions with friends
I bought BG3 on Steam instead of GoG solely to make it easier to play multiplayer with my friends.
And these features of Steam you can take advantage of even if you buy from GoG (but where would we be without Steam?)
VR support
controller support
linux support (proton)
Also there’s a much better selection on Steam. But sometimes that’s a bad sign. If a game is present on GoG and Steam, that’s a good sign there isn’t a dedication to shitty DRM, even in the Steam version. If a game is present on Steam only, you have to watch out because that game might be DRM-ridden.