The ledger is public, but the users’ identity needn’t be. And as the other commenter noted, different blockchains use different approaches, some of which do off

The ledger is public, but the users’ identity needn’t be. And as the other commenter noted, different blockchains use different approaches, some of which do offer full anonymity. You’ll also notice that I said “anonymity (or pseudonymity)”. But that’s immaterial to the discussion. The original question was whether or not the idea of digital cash (regardless of implementation) has any value.