X/Y has to be one of the most popular TCG generations barring WOTC/SWSH/current, but garners less discussion than many others
Virtue of Loyalty Virtue of Loyalty provides value at several stages of a game
Making giant tramplers is pretty fun, and I do have a Dinosaur deck I'm keen to throw this in, tons of 1/1 Vampire tokens is probably the most broken you can do with this, since you'll be doubling your counters every time you attack (though that has shades of being a really, really bad Najeela, the Blade-Blossom)
The most common way youre going to be winning will likely be due to some sort of Doomsday combo
You'll end up with a very large Juri that can hit your opponents hard, win via commander damage, or deal lots of damage to any target if removed
Giratina's price appears to be plateauing for the moment, so it will need to rely on a bit of luck to move up in value above the next card