No I do not believe that the Bitcoin is ever going to replace money because there are to many currencies for that to happen maybe Bitcoin will take over one currency from a certain country.
Even that is hard to believe that it will happen, Bitcoin has to just stay a crypto currency.
Right, bitcoin never and ever need to convert into the fiat currency, because if bitcoin has a plan to convert into money in future, so why bitcoin is coming?
I am 100% sure the day will never come when bitcoin will do it.