Jack Dorsey, The CEO of Twitter and Square believes that bitcoin will replace fiat in a decade. In his recent interview to a news channel, he said that he is sure and believe that Bitcoin will be the only currency after 10 years to used by the whole of the world and there will be no any other currency.
With that news we can say that Twitter is in the favor of bitcoin and they are supporting bitcoin. There are many other bigger personalities who are supporting bitcoin and it is the proof that the coming future will be the era of bitcoin and with it we are sure that sooner bitcoin is becoming a global currency.
If the country authorized and acknowledged crypto like government accept bitcoin of course it possible to replace fiat but for me if you think more both btc and fiat are good to have so for me there's no need to replace fiat money but see how they good at or works,Moreover all country are difference so i think they say that because of some reason