I found this expression on the news channel about the crypto currency: "Anyone who will try to buy coffee for cash in 2023, runs the risk of causing laughter from the seller, that he does not use crypto currency."
how do you think, is it realistic? Can a crypto currency replace national money?
I think that it's possible, but it will take more time.
Crytocurrency will not replace the national currency. But cryptocurrency will be allowed to be used as a medium of exchange in exchange for goods and services given the fact that the said cryptocurrency is backed up by the national currency. There is no stand alone cryptocurrency and it is observable today that altcoins is backed up by bitcoin and bitcoin is backed up by the US dollars. Thus without the US dollars or any of the national currency the cryptocurrency market will die.