I don't get it?
This guys saying money is useless because its heavy?
What about credit cards, bank transfers, cheques, etc?
Who the fuck buys anything worth $100,000 in cash besides professional poker players and drug dealers?
There are a number of reasons why actual metal currency is unideal, not least of which is coin shaving and forgery.
It would seem to make much more sense that if fiat currency was disbanded, digital currency transaction would become near universal, perhaps on a combined metal index to back it up with.