The most important by far rule for currency is stability. With stability comes acceptance of the currency. You don't have that - the owner first looked up the e

The most important by far rule for currency is stability. With stability comes acceptance of the currency. You don't have that - the owner first looked up the exchange rate to US dollars. Maybe he looked up the exchange rate rate because he wants to be fair: he wants to charge the same price for a lunch regardless of whether people pay with Bitcoins or dollars.