The following links are to various sites that discuss the alternative of digital currency, direct exchange of digital certificates which may be redeemed for things of value.
The Microelectronic Revolution, by Jon Roland, April, 1979 — Article in The Futurist, forecasting the Internet, the smart phone, nanotechnology, and digital currency that would eliminate banks. Article was republished in Eastern Airlines Magazine, and a Spanish version in a Mexican magazine.
Bitcoin — P2P Digital Currency, but increase in value makes it better as an investment than as currency.