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/2NeLgLrOf course, it is advantageous for the government to say that crypto-currencies will never replace fiat money, but we know that this is not true. The technology of blockchain and crypto currency market is still young. I am sure that in 10 years we will pay with the crypto currency everywhere.