The European Parliaments Committee on Economic and Monetary Affairs (ECON) has come up with a report on cryptocurrency entitled Virtual currencies and central banks monetary policy: challenges ahead. The finding of reports shows that cryptocurrency will not replace fiat currency, even in the long term.
https://bit.ly/2NeLgLrCryptocurrency cannot replace fiat currency since not everybody is using it. It will never replace fiat currency. There are a couple of people who are bringing it down. Fiat currency has established its roots and is very well backed by different agencies.