already owned on GOG (and that is also available on Luna)
If all that entails is the Witcher series and Cyberpunk it's no different than Geforce Now. I've bought many older games on gog that I would love to be able to stream.
This is from the blog post on gog:
whether you enjoy timeless classics or modern hits, you’ll find such GOG titles on Luna soon!
If that is true, since I've already paid a hundred bucks for a year's priority access on Geforce Now, I hope they work out something similar with Nvidia to make more of their titles available there.