Visa's underlying currency (fiat) uses *zero* energy (paper notes).
False, quite some energy and other ressources are required for minting/printing and distribution.Childish pedantry. How much energy do you think is used to print a hundred dollar bill? You think the FED is doing J/$ calculations before they fire up their printing presses?
Hint: BTC miners *do*
These will be pretty costy and you have to renew it. Think about it this way: if exact copy of 100 would cost only dollar, wouldnt this be profitable business for many?