These websites are digital storefronts that typically trade cards with players via bots
(+1: Create a colorless artifact token named Etherium Cell with "Tap, Sacrifice this artifact: Add one mana of any color to your mana pool.") That's a very weak +1 that takes this card out of the Legacy contest, maybe even the Modern contest
Essentially, you cast Amulet of Quoz, sacrifice it after a whole turn, and bet the outcome of the match in a coin flip
How can I use this system practically
An early moment in the game, the scene sees Yuna try to cheer Tidus up as the duo and the rest of the party prepare to carry on their pilgrimage to defeat the monstrous entity known as Sin, who Tidus has just learned (spoilers for a 24-year-old PS2 game) is actually seemingly a transformed corruption of his long-missing father, Jecht
Enough of sucking up to Eric Klug, already