It can give a creature islandwalk to sneak past an opponent with islands, shrink something by -1 toughness while adding +2 power to push through damage, or even force a player to discard a card
Taking two turns in a row is undoubtedly incredibly powerful, especially in a format where two- and three-prize Pokmon make up the bulk of attackers
A PSA 10 sold for around $15,000
and its quite clear that figuring out how best to utilize them is far from an easy task
Of course, you need your own creatures in play to fight something, but that wont be difficult for a green deck to achieve
Notably, Izzet Phoenix is also a popular archetype in Pioneer right now, but in that MTG format, the deck doesn't run Demilich