> Though I don't really understand why governments need a single currency. "need" is probably too strong a word. A single currency just makes things easier. H

> Though I don't really understand why governments need a single currency. "need" is probably too strong a word. A single currency just makes things easier. Having a single currency, or using many different currencies is sort of like the difference between a barter system vs a money system (multiple currencies is equivalent to bartering). If the buyer is trying to buy in a currency that is not desired by the seller (i.e. there is nothing that they want being sold in that currency), the seller has to offload it somehow to someone that does want it. There is a cost to that, in additional risk and effort. Bartering works ok, up until a point. But a shared currency just removes friction, so is preferable.