I'm sure people have already said this in the comments but you can pay off your credit card with it. All you would do is trade it to someone who thinks it's worth $11 and give that to your credit card company or bank.

It's like saying you can't pay off your credit card with Japanese Yen and asking why people value 79.5 Yen as 1USD. It's a currency used by people somewhere else and it's value fluctuates based on the two markets. It's as simple as that.