You could pick off just one character with 2 Willpower, or ping damage onto two and finish them off with another character or ability
In truth, there's more to it than that
For this added cost, you get a ton more value, as Sephiroth can easily draw you a card upon entry
Notably, greens approach to life gain is closer to blacks
Amber - Stefen Delgado Amethyst - Garrett Farrington Emerald - Dan Eckstein Ruby - Dan Eckstein Steel - Stefen Delgado This card screams "value!" On turn two you not only get to ink a second card, so that by turn three you can go up to 4 ink, but this card also replaces itself and allows you to draw
Try not to play these cards unless you have an item to banish, but Judy can also be used to banish an opponent's item in a pinch