They all produced something and extended credit to the fellow towns folk that they could trust. Everything breaks down when you have to depend on a (((third party))) for credit. That third party claims interest on every transaction, so when the money got back to the hotel it would only be $40 dollars and problems would occur. Credit and fiat currency isn't the problem, interest is. In a proper barter system I go to a mechanic and get my tractor fixed in exchange for giving the mechanic some amount of food at harvest time. As long as we trust each other, everyone's labor is converted into useful outcomes. Break down that trust with things like illegal immigration and forced hiring of unqualified "minorities". Now you can't trust anyone and must depend on a third party that takes it's pound of flesh out of every transaction.