For context, Larian Studio founder Swen Vincke predicted that the game could reach 100,000 peak concurrent users during its debut period, and that was a fairly optimistic prediction. I work in IT, and really feel for those folks. I hope they designed their infrastructure to scale!
And that’s only Steam, not including GOG, or the influx of PS5 users next month. Let’s take it to 1 million!
It’s just plainly more consumer friendly, a decidedly solid lack of DRM is one reason. Steam is more convenient, for sure, and can be a smoother experience (as OP has indicated). How bad do you want to OWN your games?
https://levelskip.com/consoles/I-prefer-GOG