Grand Resets Rewards

No, the grand reset rewards are permanent stats. Credits for grand resets has sense when there is an item shop that sells items for credits and we don't have one or when the exp is a lot higher.
We don't plan on adding credits for GR since we do not have an item shop, there are plenty of opportunities to earn credits and mupoints in-game. If we would ever do that into a distant future which I doubt then most likely you won't be able to claim them at that point unless you start a new character.