That's a pretty old discussion about bitcoin being used instead of credit cards and replacing the fiat transactions on credit cards, regardless people usually use bitcoin and other cryptocurrencies as an investment and not as a payment method, I guess nothing will replace another thing because these two are both useful in their own place and these two got their own benefits, I personally consider bitcoin as investment option instead of a payment method but in some cases, this can be a good payment method for the people who prefer using and paying with bitcoin instead of credit cards.