Right away, it's one of my first opportunities to abuse the hell out of Card Mod for magic.

Card Mod: Diablos -> 100 Black Holes
Time/Space Mod: 1 Black Hole -> 20? Demi spells

That's more Demi than I'll ever need for the rest of the game and Demi offers a better stat increase than most spells at this point in the game, so unless I'm really going out of my way with the Triple Triad grind this is my first opportunity for a major stat increase.

EDIT:

Also, why does he use Curaga on you when you use Demi? Weird.