That's great idea. However I would not expect GOG to consider it.

Yep, pay something like a minimal transfer fee, perhaps $1 per game or 50 cents.

I've gotten maybe 3 or 4 games through GOG Connect at various times over the last 3 years or so.

It was for me!
I received many games from that thing.

The best part of it was that it was sort of Desura's second life, because first I had bought some Indie Royale bundles, then when they closed I used whatever Steam keys they offered, and GOG Connect made it possible to have those games once again available as DRM-free downloads.

It's a promotional gimmick that is rarely utilized. There is little to no incentive for big companies to do this besides generating some positive buzz, since you have already purchased their product to use Connect.

Even if it's not dead, it's not worth it to me to permanently link my Steam account here. I'll never use Connect.

Reclaim your game, is another underutilized feature here.

https://www.gog.com/reclaim

I was one of the lucky ones that had two of the S.T.A.L.K.E.R games I could claim.
I didn't have the third, but bought that here for a good price anyway.

These are good options to have, and I would hate to see them be removed.
Maybe when GOG is more financial, we will see a return of activity with them ... one can always hope.