It's gimmick is supposed to be that it would scrape and integrate games from other launchers using plugins and consolidate all your PC games, friends and other tools.
Which sort of works for a while, until you try to add several thousand games, at which point the launcher takes ages to start and compile your database and generally becomes cumbersome and buggy. And once you add that stuff, removing it is surprisingly hard, so getting to your GOG games is weirdly hindered.
I love the idea, I've purchased several separate database apps over the years to try to get that exact feature. They just didn't nail it on execution and ended up with a worse version of that type of app that can accidentally become a worse launcher for your GOG library as well.
If you only use it as a GOG launcher, stick to the integrations that come pre-built and avoid plugins or if you only have a few games it's perfectly fine. Great, even. But it certainly got pretty busted in my case.