HP can help identify fakes : If a card has an HP value that doesn't match any known printing of that card, it might be counterfeit
However, promo cards are also prohibited from being used despite many of them still meeting the eligibility requirements
But Im putting this in most of my red decks and I think its going to be great fun
It also draws you a card on ETB thanks to the partner with mechanic
So even though it does seem expensive for Giratina to only be able to do 30 hp to each Pokemon of your opponent's for 4 energy, just think if your opponent has 3 Pokemon in play, 1 active and 2 benched, 1 turn of Darkness Lost can do 90 hp with 4 energy cards, which isn't bad at all
With Aetherflux Reservoir or Golems Heart in play to offset the life loss, you can draw your whole deck