It is powerful, 4 mana to start making everyone sacrifice permanents every turn is very strong, but it's at its strongest when she is your commander and the consistency of that slot can be taken advantage of at its fullest
2) with Gardevoir's card that in this secret rarity, the entire evolutionary line, from Ralts, shows a history with its trainer until its old age (very similar to what they had with Emboar LTR 27 in Black/White )
PSA 10 grades can increase value by 200-400% for high-demand Gengar variants
Only three have been officially released to players so far
Its worth remembering World Enchantments count for every creature on the battlefield, meaning your opponents creatures also have haste, and you can only have one World Enchantment active at one table at the same time
Wherever you play it, its clear that Teval is a card with massive potential