Q: Some cards say things about “when discarded”. If I use Zap A Card, the card isn’t discarded, it’s just no longer in play. Isn’t that the same thing in this case?

A: Yes, removing a card from play with Zap A Card would have the same effect as discarding it… unless it’s a Creeper, in which case it cannot be held in one’s hand, and would effectively just be moved from in play in front of one player, to in play in front of the player who Zapped it.