He wants normal banking and money transfer... but just to anybody, and for any reason. As an example, he'd like people to be able to pay him to draw bespoke furry porn for them. Or as another example, why can't a US citizen pay an Iranian citizen to do some work for them? (e.g. write a computer program)

That is totally possible. The only thing that stands in his way, and drives him into the arms of the cryptocurrency frauds, are moralising and realpolitiking governments that intentionally use their control of banks to control what bank customers can do with their money.

In an ideal world, government would only regulate banks on fiscal propriety and fair-dealing, and would not get in the way of consenting adults exchanging money for goods and services. But because government does fuck with banks, and sometimes the banks just do the fuckery anyway and government doesn't compel them to offer services to all (e.g. Visa/Mastercard refuse to allow porn merchants?), normal people start listening to the libertarians, the sovereign citizens, and the pump-and-dump fraudsters hyping cryptocurrencies.

He wants decentralised digital cash. How can it be done, if not Bitcoin et al?