That's not the only item that is only useful by being sold. Nuggets and Pearls have the same use. If you find some Carbos, Proteins, Calciums, etc that you don't really want to use, those are sold for quite a bit as well.
Just save it until you need the extra money. It's helpful then.
well, i already knew that there's no use for nuggets and pearls except to sell them, but i keep my vitamins cuz i use them. some of the incenses sell pretty well, too. and the star stuff, along w/ the evolution stones.