Cryptocurrency replacing fiat will certainly never happen. Governments and central banks will not allow that to happen. Cryptocurrencies will be the trend in the future and will exist alongside fiat. Cryptocurrencies give people more options in their payment methods or become another trusted place to invest and store assets.
Now we think replacing fiat with cash is impossible, but with the progress of the project continuing to improve I have no doubt that it could happen soon. Before that happens then we better focus on investing bitcoin.
The point of improvement is what we should pay attention to, if crypto is focused on increasing the interoperability and getting enough government certificates, there is a high chance that it will be one of the products that will be on par with fiat and could offer an alternative if it does well. So far, the application of crypto in the hands of users has really increased the level of interaction quite high but the interface is still just a game and investment, not linked to the role of traditional fiat, the certificate is not as complete as expected
I agree, this is the trump card of cryptocurrencies, but there will definitely not be a complete transition, the authorities do not want to lose control over finances