This reminds me of my first Alchemy game, where i stocked up on Alchemists, just to see them all discarded by Possession. Needless to say i was furious and lost the game...
I think with the tokens it's a bit like with Durations. Most Durations are rather weak the turn you play them, and cards that give Coin Token are best used if you can stock up the tokens.
So both times Possession hits you harder when your Tokens/Durations are ready than when the cards are in your hand. It hits much worse with the tokens, but then again it's easier to avoid it by simply spending them. I'd probably use them up every time unless my right opponent just played his only Possession, but if i know he likes to draw his deck or get many Possessions, i'd rather not rely on the tokens at all.