Disappear At the beginning of your end step, if a permanent left the battlefield under your control this turn, put three +1/+1 counters on up to one other target artifact or creature
Summon: Primal Odin If we made an Odin card, that means we had to use Zantetsuken
Removing a creature is pretty potent, so the design team decided to make it a one-time thing and turned it into an enters-the-battlefield trigger
From playing with the heroes such as Yuna, Wakka, and Auron, to even finding uses for the minor moments such as the traveling shopkeeper Oaka constantly asking you for money (though in MTG hes after your counters to exchange for drawing more cards)
These decks (and their Jeskai corollaries) are sometimes reported under the name "Flash," and that's probably an apt description of their play pattern
I'm not 100% sure where it came from, but I have to assume it was designed top-down from the creative side