The only thing I am seeing is that them being flush with scraps is becoming a problem for the game and new players. This is probably too harsh, but maybe them leaving the new Gwent will be a positive effect in the long run.
Dude, beta players would be "flush with scrap" even if CDPR hadn't milled their entire collection. Players have had full collections for a long time now. How is that an issue?
The only actual issues with new players are starter decks and how the matchmaking works. Gwent has had issues with matchmaking since the beginning.
There is nothing positive about beta players leaving.