Good Questions , Correct Answer.
Thanks for Sharing.

(Banks may soon issue cryptocurrency that is based off on their own private blockchain and hold currency values like how banks from different countries hold each others, similar to how US banks hold Naira in Nigeria to maintain the exchange rate.)

The Fourth Question:
Will cryptocurrencies replace fiat money in the future ?
I do not know to answer but :
I believe Bitcoin shall remain the currency that people use for long term investments like stock
I think that the age for trading value through fiat currencies is over. The next generation must and will employ blockchains.