My opinion is that in future transactions BTC will be more dominant when all stores provide the option to pay using digital currency. Fiat of course will not disappear either because there are still remote residents who use it as a means of transaction only if someone wants to shop in many categories and large values are too vulgar to carry but if in BTC just one click is done.
It will be more successful when your country allows transactions using bitcoin and maybe that challenge is what must be prepared first because allowing bitcoin to be a legal means of transaction will create greater competition with fiat currency so that the government may try to limit it. Bitcoin is indeed faster for transaction matters but it cannot be fully implemented because it concerns the regulations of each country that may limit it. It is impossible for people to do something that is prohibited because there will be consequences that will be obtained when violated and allowing bitcoin as an investment is more than enough for now.