Before Worlds 2012, Mewtwo-EX was good for a lot of different reasons, but Mewtwo-EX continued to be played after that in most energy acceleration decks just because X-Ball was such a strong attack
Its nostalgic elements and gameplay-ready updates helped bring a resurgence of interest in the Pokmon TCG when it was released.
Do keep in mind that it sits atop hundreds of other Eeveelution cards that exist in the TCG
Ultraviolet (UV) Light Protection: Advanced UV shielding ensures your cards maintain their pristine condition while lesser cases let theirs fade away
On all subsequent turns, having opposing creatures die means making more Treasure tokens, which should happen often if the player is running red, the color of burn spells
First, all your creatures get a +1/+1 buff and gain double strike, ensuring a really big swing - though your opponents will see it coming