If you sell crypto for fiat on a hardware wallet, it won’t be cash, it’ll be a stablecoin, like USDC, USDT or DAI.
If you want to spend that “cash” you’ll still have to enter the legacy banking system to do it.
(Unless you transact with somebody who is willing to accept the stablecoin, that is becoming more commonplace now, especially in Africa, Asia, etc).
