Just to expand on the point: there's two models of currency: fiat and commodity. Commodity money is obviously linked to an existing commodity, and suffers from massive swings since there's no way to insulate it from "news". BitCoin, of course, isn't backed by a commodity, so the natural thing is to assume it's a commodity in an of itself. The "mining" terminology supports this view, obviously. As a commodity, it most closely resembles Gold, in that its value doesn't seem closely correlated to the value one can extract from it through industrial use.
Fiat money has its plusses, though. Directly related to the fact that governments _can_ manipulate them is the possibility of reputational currencies. Here, a state has managed its fluctuations and taken actions when prompted for sufficiently often that "news" affects them much less than commodities, since the markets assume the state will act well before it becomes an issue (this also damps good news, since to a certain effect the good news was "expected").
A good study in this phenomenon, and how to break it, is what's happened to Britain since the referendum. It has lost a lot of value, obviously, but also its volatility has gone sky-high.
Going back to OP's point, a well-managed fiat currency can be a better store of value than any commodity. Entertainingly, Sterling has lost a similar amount of value to BitCoin, but it took much longer and is regarded as a disaster. Although, like BitCoin, you'll be able to find fans swearing the exact opposite.