If it's a creature card, put it into your graveyard
Pushing your deck above 60 (or 40) cards makes it harder to find key cards, increases the risk of "mana flood" (drawing only lands, so you have nothing to cast) and "mana screw" (drawing too few lands, so you can't cast any of the spells in your hand), and makes it more likely that you'll draw unplayable hands
Similar to how Mewtwo was forming an offensive move, Charizard is posed up, ready for a fight as they surround themselves with fire, making this, some could say, another fire choice
More details on the PFM events and prizes can be found here
A drawback is one of the many knobs Magic design can use to balance a card