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/2NeLgLrIn my opinion, well, even though bitcoin will not be able to defeat the fiat currency it will have a good and bad effect on bitcoin users with their own perspectives. For me, it wil be a good effect on bitcoin because if bitcoin will defeat fiat currency then there is a chance that the government will held the bitcoin and start to regulates the cryptocurrency. So, I think it is better that bitcoin will not surpass in bitcoin in terms of usage, but in terms of price I thinks its bitcoin.