It's a great tradeoff to transform an opponents best creature, hopefully their commander, into a minor threat
4 Primeape Drawback: Debuffed Attack The new Primeape is one of the weirdest cards in the Mythical Island expansion
(The Discard Pile is where knocked-out Pokemon, any Energy that was attached to them when they were knocked out, and all used Trainer/Supporter cards are piled up.) This rule helps prevent people from stalling into eternity and offers a potential downside to trying to stuff one's hand with dozens of cards at once
It also has a cool dice component (yes, luck-based)
No problem more Treasures for you
He buffs the power of your Plants and Treefolk, opening up aggressive strategies for both, and also lets you dig one up from your graveyard each turn, to replace those that fall in battle