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.
Bitcoin will not replace fiat but after knowing bitcoins people will reduce the usage of fiat for sure as even now people prefer to shop using credit cards so once they are aware about bitcoins they will surely switch to bitcoins for making payments.
Credit card is different from bitcoins. Credit card might also be digital but it's all about credit. People are addicted on using credit card because they are able to buy stuffs right away even when they cannot afford it yet. Bitcoin, on the other hand, is like the counterpart which is the debit card. Imagine a debit card that allows you to send money abroad without doing that much and without paying much. That's how bitcoin is
Do you have a debit card yourself?
Card-to-card payments are instant (and they are truly instant unlike Bitcoin payments), and in many cases they are either cheap or entirely free of charge. On the contrary, Bitcoin transactions nowadays are already far from being cheap, they are no longer cheap by any means. Apart from that, people often use the phrase credit card synonymously with just a payment card. They don't necessarily mean it to be a real credit card (I agree this is an incorrect usage but we have what we have)