A digital world is great to live in for digital beings, but we are not digital. We are flesh and bones. And we need somewhere physical to stay, something physical to eat. These are the basics that mean we still need a physical country and/or governance.

However, I do agree that with digital money we should be free to choose what "currency" we want to recieve for work, payments, etc... People want stability, so the more stable the digital currency, the more I think that people will trust in it. Hyper-inflation is almost as bad as deflation.