There is no such thing as digital cash outside of cryptocurrencies.

The money in your bank account is a liability of the bank, it's not cash.

You can go through life without ever using physical cash. You get paid digitally, you buy groceries digitally. You even borrow money for a house digitally.

The thing you transact with is digital, liquid and fungible. In what sense is it not cash?

All those transactions are reversible at any point with a flip of a bit (or two).

If you receive physical cash, it's in your control.

Now if only that cash could not be inflated as much as it can.

I don’t think any common definition of cash includes the idea that payments are “irreversible”. I don’t even see why this is so important. If someone pays me physical cash by mistake they have legal recourse to get it back. It’s not finder’s keepers.