Don't you understand? None of that will matter in a crypto currency based economy.
The only reason you need to deal with fiat now is because few accept crypto, and none pay crypto.
Think beyond 10 years. Think beyond 20.
A crypto currency based economy would still not be exempt from all laws. And if laws can't be imposed it will be illegal. And if it is illegal then you will see no 'crypto currency based economy'. Wake up.
You do realize that a cryptocurrency based economy can exist over borders and circumvent through government laws right?