Edited sentence: And sometimes, paper money fails rather quickly, too.Gold and silver are perfect examples.Gold and silver have been trusted stores of value for nearly all of human history.Gold and silver have historically had the lowest transaction costs, until a standardized, national, Federal paper money replaced them.Low transaction costs to buy and sell the item help it to become a medium of exchange, since it is easier to buy and sell it than any other item.Paper money always loses value over time, and is a horrible long term store of value.Since the U.To be a unit of account, the item used as money needs to be measurable, and divisible.Unbacked paper money fails to be measureable in terms of value, and becomes measureable only numerically.government will soon stop reporting M3, the dollar will become a unit of account with no accounting