If a CBDC is properly made, then it should work similarly to cash, as in:
- no central ledger of transactions, instead a central registry of valid coins (like there’s a number printed on every bank note)
- accounts are independent on any central service, they should be able to run locally (3rd parties might offer some kind of backup services, but generally people would still also use regular bank accounts to store most of their money to protect from device failure, because these can break or be stolen, same as regular wallets today)
- coins are indistinguishable from each other, except for the serial number. There might be a central register of revoked coins but that shouldn’t matter too much because in general it wouldn’t be known who owns what coins.
Now of course any state could decide to make up their own version of a CBDC with vastly different features, so really in general it’s hard to say what the advantages/disadvantages are without focusing on an actual implementation. But I don’t think it’s a smart move to just dismiss the idea completely. Ultimately at some point in the next 100 years or so we will probably stop using coins made out of metal and notes made out of paper, and if we want something like https://taler.net to be used in their stead, and not some of the things you dream up here, we need to promote the better way forward, and not preach that we shouldn’t move on. Because move on they will anyway, just not in the right direction then.