In response to this, I think of the service provided by bitpay.com. They offer merchants the ability to accept payment in dollars (or many other currencies) on their website/app and receive the payments in dollars (or other currency). There is a middle step where bitcoins are bought and sold. There are some benefits to the merchant as versus 'traditional' online payment methods ie. better security and "cash-like" online purchases. It is abstract, but I believe that this example illustrates utility that bitcoins (or other crypto-currencies) provide.