It seems like the possibility is still small if indeed it happens, anyhow fiat is a characteristic of each country that has different currencies, unlike crypto, I think crypto will only be an alternative currency that's indeed like as a global currency for each country.

We really don't know what's going to happen but let's consider the fact that we are already on digital technology,so there is possibility that crypto will be the replacement of fiat in the future.

In my humble opinion we will not face any replacement for a few years from now if ever because cryptocurrency and the people around to be honest are far from being ready to use crypto currency as a payment method, what about you?

Cryptocurrency has gained popularity and has spread all over the world in different regions or countries where there people are enjoying this new way, is public friendly acts as investment source as well as transaction mode that costs less and frictionless and we do not need banks those do for us in days on high rate. Banks replacement is looking impossible as long as government does not think on it.

Crypto for now don't have chance to replace fiat currencies as only few people are supporting cryptocurrencies now. Maybe in the future we can hope that digital currencies will be accepted worlwide.

For large transactions, cryptocurrencies can be used, but can you imagine when a 7-year-old boy buys candy to pay using crypto?

What happens is clearly a payment problem. To replace fiat money, I think it's impossible. But to align with fiat money is very possible.

Only functions and uses can differ depending on needs. Crypto money is a sophisticated technology that can definitely add value to financial transactions because digital currencies do not have physical, but banknotes cannot be replaced because they are practical and have physical properties.

yes, discuss about the taxes and regulation, and at last crypto will not be a free as nowdays

I think crypto is being used by the elite to replace fiat.  Once the blockchain is in place we will all be tax mules as every transaction world wide will be caught.  Keep filling out the KYC guys.  You will end up enslaving yourselves and your children.  

Although it is unlikely that such a situation will occur in the near future, I think it is possible to realize this in the coming years. Even if the transition is not complete, countries may market digital versions of their existing money, and cash usage over time can be completely abolished. Of course, if this happens, this market will be affected because if all states start accepting crypt money as an official currency then regulation will also be necessary. That is why I think it is very unlikely that there will be such a situation in the near future, but I think that it will be considered in every detail in the long term and that the use of cash will end in the future. Of course, estimating time will not be easy, but I am not likely to see it happen in the next 20 years.