No, I do not think BTC or any altcoin will REPLACE fiat anytime soon as cryptocurrency is alot different than fiat so people will need proper education and a huge amount of adaptors to consider BTC at least as much important as fiat and even that time BTC would not replace fiat, just grow next to it in popularity.
The whole point that people fail to understand is that Bitcoin DOESN'T need to replace fiat.
Totally agree with this. It is still more convenient if we have lots of payment option than to rely in only one institution.
What if there's no internet? What if no device where available? Can bitcoin can help us with a situation like this?