I think its safe to say that bitcoin will never replace fiat in our lifetime. The currencies are matter of faith, and for the moment bitcoin will remain a side player. Will it continue rising in popularity? I think yes. To the extent that it becomes successful, it will serve as a complement to fiat currencies, as well as other cryptocurrencies.
Yeah bitcoin will become more popular in future but people will prefer to use it as a secondary currency and will use it only for online purposes and to buy anything offline they will choose to use fiat as fiat is widely used and accepted in compare to bitcoins.