Volatility is a serious problem, if you’re trying to put together a currency, rather than a vehicle for financial speculation. If the currency of a country ever fluctuated as much as bitcoins did, it would never be taken seriously as a medium of exchange: how are you meant to do business in a place where an item costing one unit of currency is worth $10 one day and $20 the next? Currencies need a modicum of stability; indeed, one of the main selling points of bitcoin was that it couldn’t be destabilized by government institutions. But that comes as scant comfort to people watching the value of a bitcoin behave like some kind of demented internet stock during the dot-com bubble.
In reality, then, bitcoin doesn’t really behave like a currency at all. In terms of its market value, it looks much more like a highly-volatile commodity. That’s by design: bitcoins were created to be the most fungible commodity the world had ever seen – to the point at which they would effectively erase the distinction between a commodity and a currency.