People are creatures that live in society. At first it was a herd, but now it is a more complex social superstructure called the state, on behalf of which the government acts. We need such a social structure, because without it, without establishing general rules of behavior, any strong would allow himself to take away the property of the weak. In order not to carry with him sometimes heavy objects and values that played the role of money, a person invented paper money that began to replace them. As a general rule, paper money should be printed as much as material values exist in the circulation of the state. That is, cashless and cash are closely related to the economy of each state.
Cryptocurrency is a completely different type of financial asset, which cannot fully replace the state's money. Under certain conditions, paper money of the state can be replaced by non-cash money of this state.