I still do not know a single person who would live using only cryptocurrency. Apparently, I hardly ever find such a person. Cryptocurrency will always occupy only a certain part of our financial relationship. We will always need a common currency; not all structures will accept cryptocurrency as a means of payment. I know that many fundamentally will not use it. Cryptocurrency can only be used along with the national currencies of the states and will be one of the non-cash forms of payment, and very specific ones.
That is correct, we cannot completely scrap the use of Fiat in our transactions a we definitely need it to have crypto in our wallet, and so long cash still exist, Traditional banks will still be in existence, but then, when it comes to payment system, crypto can completely replace Fiat and scrap the involvement of banks In that regards.
Although it will be more useful to merchants that uses the service of internet to sell their product or technology devices, the moment all online merchants introduces the use of cryptocurrency for payment would be the end to fiat payment, and for the local store, I am sure crypto POS will be introduced soon that will enable them to make crypto payment without using fiat. So the power of banks over our finances might go down to 10% over time.