Crecente detailed several fine reasons to purchase Super Street Fighter IV. Capcom's GameStop-exclusive preorder bonus is not one of those, unless you have really cold thumbs.
Yes, it's Super Thumb Fighters, eight thumb socks emblazoned with the faces of your favourite Super Street Fighter IV characters. I suppose these underachieving sock puppets will give players something to do in case the power goes out and they can't play the game proper, but other than that I cannot think of a single good reason to have Chun-Li's face on the tip of your thumb.
I said good reason. That is not a good reason. Stop that.