Of course in practice it is a chicken-egg situation. Few people will use it over established credit based systems unless there are other incentives.
Credit card companies, including PayPal & Co, are essentially rent seeking: They are middle men that technologically aren't needed anymore for instant cashless payments, but they still exist because they can extract enormous amounts of profits via fees. But countries like Brazil and India show that they can be replaced with free or almost free systems based on instant bank transfers.
It's true that credit cards still have the use case of providing a "chargeback" service. But this isn't possible with ordinary cash either. Moreover, most people likely buy online from trustworthy shops like Amazon, so this isn't often a problem in practice. In expectation people spend way more money on credit card fees than they ever save with chargeback. Chargeback is like an overly expensive insurance that hardly anybody needs.