Bitcoin have the big chance to replace fiat. Becouse people in some countries were change their money in to bitcoin to save their wealth when their fiat price is fall against USD. Those country need to import logistic that they have to pay with USD. So I think people will prefer like to use bitcoin than fiat.
People would surely love to use bitcoin instead of cash if they come to know about it, but we also should not forget that those people are not able to do that themselves but they have a government which decides what currency will be used in that country.