Making money this way is not dumb. It's done daily on the stock market and many people have built their wealth doing that. What is dumb about Bitcoin is the built-in assumption that scarcity of the currency gives it a real value, where in fact what gives it value is it's use in commerce (and more specifically how widely it's used.) If it was up to the Chinese the dollar would be dead. But no one is there to protect Bitcoin's turf. Here today, gone tomorrow.