It seems unlikely that such a scenario will take place. I don't think governments will allow such a structure that they can't control, they can make their own digital currency in future, but that's gonna be much different from current fiat currencies.
No, actually it could be the same or they could stay with the credit and debit card system. Just a card and no papers.
This will be a problem with the poor side though.
They will be forced to have an account in the bank and deposit some money if they need to transact something.
If digital currency is what they will create then it might just be the same as fiat. Just made it online. Same as USDT, something like that.
