Why cryptocurrencies are useless?

The price of bitcoin for December 2016 was $900 and in just one year it grew to$ 19,000. However, later the famous digital currency suffered a sharp depreciation to collapse to $ 7,000. Now nobody knows where their value will go in the future.
Bitcoin was devised as a techno-anarchist project that involved the creation of a type of online cash. This cash would have to offer an opportunity for people to make transactions without interference from banks and governments.

According to the magazine, in order to implement this cryptocurrency, users had to struggle with a complicated 'software' system as very few vendors accepted digital money as a means of payment. In addition, security is very scarce.

A demand that could sustain its value and limited regulation contributed to the fact that bitcoin and other cryptocurrencies became a source of speculation. Some people amassed great fortunes when their prices went up, while others lost all their money.
Economists, according to the British magazine, define a currency as something that can one day become an instrument of change, a reserve of value or a unit of account.

"The lack of approval and its volatility indicate that cryptocurrency does not correspond to any of these criteria, but that does not mean that they will disappear in the future." There is little reason to think that [someday] cryptocurrency will become something more than a casino that is too complicated and unreliable, "the media concludes.