Of course, Fiat currencies are still necessary for society. Not all people are adapted for cashless payments. Many even abandon it or use it as necessary, when there are no other options.
Agree on you . not all people can use cryptos because not all have the knowledge and tools to use it .
Poor people are the ones that im referring to . they are the ones that is totally affected if ever the cash and fiats will be extinct on the future
But i believed that wont be happening anymore even if we say that cryptocurrencies will become a global hit . devs and inventors will rather import the crypto into a coin and paper like shape , so that others can also enjoy the benefit of using it .