Bitcoin is still very very young and of course it won't be replacing fiat anytime soon. But who know what will happen in the long run when the price stabilizes? Who know what will happen in a decade? Bitcoin will gain momentum and, very possibly, most people will be using it somehow.

Of course, not everything is as straightforward as that. Bitcoin is not tangible. This is the main factor why it will not be able to fully replace fiat money, whatever happens.