What would be a real-world use case for a cryptocurrency that is not a scam?
The use cases for existing cryptocurrencies seem to be:
a) cutting out traditional financial institutions who take their cut from every transaction, and having a pure peer-to-peer transfer mechanism. But while this cuts out traditional gatekeepers, there are still transaction costs on a crypto network (sometimes quite high)
b) cutting out traditional financial institutions who take days to execute a transfer, and have an immediate (or quasi-immediate) transfer mechanism. As pointed out in the article, this can be improved at least locally within a country by upgrading the traditional banking systems. Something that also needs to happen internationally.
c) allowing poor people access to banking services. Traditional banks are only willing to deal with people who have some money, so they can extract fees. Many people in the developing world have no access to banking services eg loans. Crypto allows a person to use their mobile phone as a cash wallet without having an intermediary hold the money in custody. There are pluses and minuses to this, but of course when someone doesn't have a lot of money they might prefer total control over what little thy have than deposit it at a bank. People with thousands / millions, on the other hand, are probably happy to have that deposited or invested with a reputable financial institution for a reasonable fee. Having a mechanism where network users can do peer-to-peer lending in a controlled (non-loan-shark) environment could be a good use case.
d) anonymity, although in crypto by definition the accounts are public the account holder can be anonymous. There is some scope for anonymous money transfers to happen, especially for people under repressive regimes, but lets face it a lot of the people wanting the anonymity want it to avoid tax or for criminal purposes. This is pretty much by definition a use case that no user would sign up to a central bank cryptocurrency for.
e) inflationary control, ie not allowing the network to arbitrarily generate tokens and thus devalue existing tokens. I don't think any central bank digital currency could offer this or would ever want to offer this.
Basically, apart from point c) there isn't much that uniquely requires a distributed peer-to-peer financial network. Although I certainly hope that pressure from cryptocurrency and new 'digital-only' banks starts steering traditional banks offer such 'luxuries' as real-time money transfers and non-extortionate international transaction rates