Harmonization is what will enhance the existence of the cryptocurrency, this will only happen when government globally has a stack in the decision making for this to work out, thou crypto is still evolving and this might not happen soon.
For the future, it can happen using fiat and crypto together, where there are no more problems because fiat is a traditional payment while crypto functions digitally. People are welcome to choose which one to make payments.
Today even though many people have been combined both, and the results are far better than using just one currency. there is no need to drop each other which one is better between the two, while using both of them simultaneously, provides easy transactions for you
right, with the many choices of payment methods, of course, make consumers more free to choose. and I think this will have a good impact on the pace of the economy. Of course to drop fiat at this time is very difficult, even impossible, because it requires approval from all countries, because bitcoin does not only belong to a country