"I don't really see the need for a central authority and you'd have to make a really good case to convince me." A central bank can ultimately control the value

"I don't really see the need for a central authority and you'd have to make a really good case to convince me." A central bank can ultimately control the value of a currency by either grabbing assets on the free market and emitting currency - or the inverse - grabbing currency and selling off the underlying asset. This is a very powerful way to control volatility. Gold has fairly strict supply and it moves around a lot. If the US Fed really, really wanted to control the USD vis-a-vis some other currency, they could do that. "I believe most currencies originated in a decentralised way" Ah? No, definitely not. Except for gold ... currencies have issuers, rules, a central bank of sorts. Like the King. Or whatever.