Derivatives could also reduce risk for users. For instance: you're a business that accepts bitcoins for payment. But the price of bitcoins can fall by 50% in a day! So you'd better transfer those bitcoins to cash the moment you get them, or you're subject to losing half your cash any day. Something that's too hot to handle like that kind of damages the ability to use it as a medium of exchange, doesn't it? But you could alternatively buy bitcoin currency futures, essentially locking in your current price. So maybe you could hang onto those bitcoins a while and use them to pay people for your referral program or something. (Oh, sure, there's a cost associated with it, but there are costs associated with translating cash back and forth as well. Depending on the price of the derivatives, it might make sense.)