With Gerald, it's one of those moves where if it works out, great! If it doesn't work out, it doesn't matter. Celtics aren't paying him substantial long-term money, so they can just waive him.
I've already said a few times why I think Gerald could be a great fit next year (Thrives in a pace & space system, decent 3-pt shooter on a team that relies on 3-pt shooting), but I won't be too upset if he isn't.