And if you never use the tokens for any of the turns? Sure, you can wait to use them up for another play of Possession, but that just forces your opponent to use them up before that next play.
It was more of a joking reply anyway.
But seriously -- if your opponent was foolish enough to leave coin tokens available after you had purchased Possession, thn maybe you
should leave those tokens alone for future Possession turns, especially if you can play Possession enough that you expect to use their deck more than your own.