The 'unit of currency' is immaterial. It all depends on whether or not it is usable by ALL players. In a prison, they often use cigarettes rather than some mone

The 'unit of currency' is immaterial. It all depends on whether or not it is usable by ALL players. In a prison, they often use cigarettes rather than some monetary currencies. Maybe in the future, the 'unit of currency' could be 'barrels of oil', grams of gold, grams of platinum, etc. The US has blocked too many people from using the Dollar that the Dollar is not as 'universal' as it once was. So people will look for another alternative, or even many alternatives.