There are two clear clauses that limit this card
Retrieved 2011-02-22
On top of a winning condition revolving "Knock-outs," mechanics are also based on Pokemon concepts in the video games: Evolution, Energy Cards for casting (Pokemon Types), buffing Pokemon (Tools and Supporters), and altering the state of play (Stadium, Trainer Cards)
The mini Trumpet Blast is good too, it just isn't a reason to play this
If the creature that died had -1/-1 counters on it when it died, Host of the Hereafter's ability will put those on the target creature as well
In addition to being a beloved character from a fan-favorite Final Fantasy game (in this case, Final Fantasy X ), Yuna's card has some powerful utility in-game, able to bring discarded enchantments back from a player's graveyard