Hi folks, can anyone explain how to use the MINT prepaid for donations in europe?

On the warmane donation site I read "Donating $10.00 awards 10 Coins", though I can only donate 10 Euro (which is about 12 USD) for 10 points. When I want to buy from MINT, I can only buy 10 USD - wouldn't this be less than needed for a 10 Euro donation?