What provided cryptocurrencies?

Today cryptocurrencies have no material security in traditional understanding — they are not provided with gold and exchange or commodity reserves, not supported by the economy of this or that state.

The cost of cryptocurrencies is determined only by a consensus of users — their cost is determined by demand. But it is also possible to tell that cryptocurrencies are provided that they are accepted as payment. Besides, cryptocurrencies are to some extent provided with the computing power of the equipment for mining, the electric power, and workforces — that is quite physical quantities.