People calling cash as trash does not live in the normal world, no matter what technology will become popular, it will never be as useful and as popular as cash, so no.. cash is no trash.
I know right, but the guy is referring to the cash in terms of investment asset. Of course cash ain't useless, obviously as long as you're using it. The OP's title gives us a lot of misinterpretation on his statement.
This guy refers to always choose investments such as Gold, Stocks, or Bitcoin rather than storing fiat in a bank or anywhere else that can be affected by hyperinflation.