Now I've thought about it some more, bitcoin is starting to look like fiat money that's backed by nothing but trust. How's this differ from, say, coca-cola caps? Bitcoin does require energy to mine it, yes, but so does collecting coca-cola caps (although collecting them would be much cheaper per unit). The cap has no other value, and cannot be altered in ways that can become valuable (unlike gold). If coca-cola cap is now demanded by the market (for instance, in the post-apocalyptic world known as Fallout), it becomes valuable based on the supply and demand. However, when the demand for the cap has disappeared, the price of the cap will drop like a meteor, regardless of the cost that was associated with mining the cap.Same as the caps, Bitcoin has no other value other than the value assigned to it by the free market's supply and demand, and cannot be altered in ways that can become valuable. The mathematical equations your computer has to perform does not benefit any other. The value of the Bitcoin depends solely on the perceived users. If they believe it is a currency that can be used to purchase items without going through the government, Bitcoin will retain its value. If the government cracks down on Bitcoin, or that some events occurred results in a massive drop in demand of Bitcoin, it will become useless. So again, the value of Bitcoin depends massively on whether or not the users believe in this currency.

Gold on the other hand, will always retain some sort of value, due to its usefulness (especially in high tech / space industries), and the property of being attractive. So gold does have an intrinsic value associated with it. Bitcoin, on the other hand, does not.

Source: forum.xcpus.com