I agree that GOG needs to port their client to Linux for all the reasons you stated, but as a workaround you can use Lutris which lets you log into your GOG account and download+install games (Windows games too).
It's not as pain free as Steam, because you sometimes still have to apply wine fixes, but it works well with the most popular games.
It's not as pain free as Steam, because you sometimes still have to apply wine fixes, but it works well with the most popular games.