For me, it is a certainty that cryptos will never replace fiat currencies. There will be a parallel economy and the btc will become a currency like USD, EUR etc... with a parity for each pair, but not a substitute currency. And that's good, because the global economy would be shaken up, it wouldn't make any sense.
Yes cryptos have it's own use and it can never replace the real fiat currencies and even if we start using crypto instead of real fiat then it will create a chaos which might lead to a disastrous economical recession. Cryptos can be used as a mode of money transfer and other new technologies which gives i upper hand compared with traditional method like money transfer system which takes m\weeks if we do it through any money exchange but it's a matter of seconds through crypto.
Bitcoin wasn't made for remittance service,it was created for medium of transfer unfortunately many people don't use it for what is was supposed to be used.
May not create much chaos to the people,only will be a problem for the government and they will re-assist to the condition sooner.
bitcoin was not also mean for investment but people invest on it therfor bitcoin can also be used for remitance and any other use depending on the user . bitcoin is orginaly created for currency use but until now there are people that use it this way . using crypto wont also make a chaos as long as the use is appropriate . economic situation around the world are different from country to country , by using cryptos the economy can be improved if its in bad condition