I think the gimmick is part of the total package. You could buy crazy shakes with a cupcake on top before Toothsome, but they added in that steampunk vibe and no question it helped garner attention (tho I'm still not sure why exactly). Can sell the best cookies in the world, still helps to have a gimmick.
It also says "black magic." Clearly going for a cool kid Satanism Lite vibe to appeal to the Hot Topic crowd. Because, see above, everybody needs a gimmick.
Watch how quickly Everglazed fades because they don't have a gimmick.