We can have the cryptocurrency as the daily currency but somehow it will make a massive transition from small institution to larger institutions and especially on us the user. But also it will detect some problems as soon as it is implemented nationwide or worldwide that we still not so sure about. For now let us just use bitcoin as a cryptocurrency and digital money.
Not all of us have appreciated the use of bitcoin especially those areas that crypto isn't accepted as a form payment. Actually, only a few establishments are in with Bitcoin, accepting this aside from fiat. This means that the user of crypto isn't that of huge numbers than of considering this as an investment.
Fiat will still be the top in any form of currency/money accepted, yet we are in mass adoption but somehow they'll never use of crypto as mostly they use to convert it into fiat money just like in our country.
I am not of the opinion that bitcoin will be able to replace fiat, but you dont expect a new system to get full appreciation within a short period of time, people might not appreciate its use now, as things becomes clearer with time, many people will see the need why bitcoin is more useful than FIAT, the only reason why I keep believing that cryptocurrency wont replace fiat is just simply because of its technology nature.
since bitcoin operation solely depends on internet technology, people who would never be exposed to the use of technology are the ones that will make fiat remain recognized, but mark my word, with time, the usage of crypto will be far higher than fiat.