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.
I prefer crypto currency compared to fiat money because the price is not stable. I can take advantage when the price of crypto currency price increases. if fiat money always has a stable price because it is set by the government. no crypto currency can manage to keep prices stable and therefore the price goes up and down depending on buyers and sellers in the crypto currency market.
I also think that someday bitcoin will become a global currency because at this time people are getting more and more familiar with bitcoin and they will do business on crypto currency.