>I just want my games to launch as seamlessly as they do from Valve's UI

Valve integrated steam all the way down to the OS level to do all that. GOG galaxy meanwhile is focusing more on being an accompanying app to optionally use than centralizing everything under GOG. I think Galaxy trying to strive to be as "seamless" will break the very philosophy of GOG to begin with; being a store to grab games you truly own, not a platform to immerse yourself in.