I remember a system I was working on where I was setting up an empty financial account. Error - no currency specified. Well a) I don't have a currency, but more

I remember a system I was working on where I was setting up an empty financial account. Error - no currency specified. Well a) I don't have a currency, but more importantly b) how does nothing need a currency? It's as if a farmer had a field with no animals in it and was asked what sort of animals it hasn't got in it. I think the Romans were right.