Complete Fiat Replacement

They are unsound. But physical barter is cumbersome and the same effect can be achieved with community script. Especially the ones denominated in time units. What can be more valuable than time?

http://www.ithacahours.com/

Still, there could be instances when physical barter would be useful. A farming community could drop off a truck load of pig poo-poo at the United Nations to pay their "carbon taxes" with. Then video tape the facial contortions from the UN's marxist in charge and sell the video on the Internet for federal reserve notes.