In the Pokemon Trading Card Game, a cards power comes from a combination of damage potential, strategic abilities, durability, and how well it fits into competitive decks
He also serves as a cost reducer for spells you cast but dont own, which experience tells me because of my many attempts at theft decks will be really good
As examples, the rarest non-serialized drops have been the Lost Legends rares (Roughly 46,700 packs for a specific Legends rare out of DMU), the first set of Surge Foil Realms and Relics (~3,900 packs),and the Jurassic Park Emblem Foils (3,800)
But its also a useful card in legends decks, enchantress decks, and whatevers going on in Kathril, Aspect Warper decks