Yes agree, the future of the financial world is cryptocurrency, we are not too late to follow, I'm sure 20 years longer all transactions will use the cryptocurrency.
I think it is impossible for all transactions to use cryptocurrency, this is because until now cryptocurrency is not in physical form so the use of cash is still a lot.
The reason why it is called a digital currency. Why would anyone make a physical coin of it, that will be the reason that bitcoin might drop dead. Also, the reason why crypto currencies are not used for all transactions is because it has a volatile price and it is not that popular to be used by many people.