The same as any other coin ... whatever value someone chooses to pay for it.
On a slightly related note ... I found an auction website that is selling 1 oz bars of .999 silver, starting at $1.
The funny thing is, people are actually bidding up and buying those bars. Yet the price of silver is only around $0.50/oz
So people are choosing to pay TWICE (or more) what it's actual value is.
Proof that if people THINK they are getting a value, they will actually spend MORE than an item is worth.