Bitcoin (and similar) are the only truly global digital cash assets.

We could build a digital currency that was secured by public cryptography, totally anonymous, tradable without involving central authorities, and verifiable offline/by third-parties. It would require no blockchain, consume no natural resources (anymore than, say, VISA), and plug seamlessly in to the existing banking system.

No government, however, would allow such a beast to be on the Internet: global, unrestricted, and free of capital controls. In order to redeem or refresh the tokens you'd need to be a citizen and have a bank account.

That's the only unique selling point for Bitcoin.