Sorry, I didn’t make it clear. I don’t believe that there will be separate bank crypto. I’m betting that there will only be one eFiat currency for each economy.
Just as you can have coins and notes in hand, so you will be able to hold eFiat on your own device on the chain, as with any crypto. The banks will simply act as exchanges. They will also continue to issue new eFiat as loans, and act in all the other capacities in which they now act (eg investment adviser, investor, insurer, etc).
You are right that crypto presages a new financial system. But I’m also betting that it will be a radical evolution (not a revolution), with the central banks very quickly adopting the technology. It will mean that we will end up with a stable system that is no longer at risk from any bank failure, as the eFiat in circulation will not belong to any bank.
Once the Central Bank agrees to issue eFiat, you will be able to withdraw it and hold it under your personal control like cash, because it will BE cash.
The only difference is that instead of the central bank having the mint print notes for delivery to your bank for you to withdraw, it will simply issue eFiat directly to your bank which you can then withdraw electronically.
When the central bank issues notes and coins to a commercial bank to pay out a depositor, it replaces the depositor as the creditor of the bank, so both the central bank and the commercial bank’s assets and liabilities remain in balance. It will be the same with eFiat.
