My guess? It's uncommon because it probably doesn't sell well. As for appeal, it's not the most intense and also probably not the most effective (as in, I dont know how many people would find that hair tickles them, much like a feather doesnt). Additionally hair tickling has special requirements from the 'ler, specifically longish hair that can be used in such a manner. After that, well, different people have different textures for hair, making it a not-so consistent method with which to tickle, anyway.
But, like I said, those are just guesses, though the amount that I came up with would indicate it's probably too situational to have regular use.