You can't spend bitcoins at Amazon.com or to pay your mortgage but, as the Winklevoss twins showed on Wednesday, you can use the digital currency to book a trip into suborbital space.
Cameron and Tyler Winklevoss, who famously accused Facebook Inc founder Mark Zuckerberg of stealing their idea, said they used bitcoins to buy tickets for a high-altitude voyage on billionaire Richard Branson's Virgin Galactic commercial spaceflight venture.
The brothers, Olympic rowers who earned MBA degrees from Oxford University, have become bitcoin evangelists and investors and are planning to launch a fund to make it easy to trade the digital currency on the stock market.
In a blog post, Tyler Winklevoss compared Branson's space endeavor and bitcoin entrepreneurs to major historical figures who changed the way the world was perceived, like Marco Polo, Christopher Columbus, Vasco da Gama and Nicolaus Copernicus.
"It is in this vein that Cameron and I contemplate our tickets into space - as seed capital supporting a new technology that may forever change the way we travel, purchased with a new technology that may forever change the way we transact," he wrote.
Virgin Galactic, a US offshoot of Branson's London-based Virgin Group, is selling rides on its SpaceShipTwo for $250,000.
The twins are not the first to sign up for Virgin Galactic using bitcoins, but it is the highest-profile flight booking to date using the currency. Last November, Branson announced that a flight attendant from Hawaii had become the first person to pay for a seat with bitcoins.
Bitcoin, a digital currency that is traded on a peer-to-peer network independent of central control, has seen its value soar in the past year as it gains attention from growing numbers of investors, entrepreneurs and regulators.
But the virtual currency's struggle for legitimacy has been shaken by recent debacles, including the collapse last week of Tokyo-based Mt. Gox, once the world's dominant bitcoin exchange.
Few major retailers have begun accepting payment in bitcoins, and critics say the currency's high volatility makes it unsuitable for everyday transactions.
The six-passenger, two-pilot SpaceShipTwo is hauled into the air by a twin-hull carrier jet and then released.
The upcoming flights are designed to reach altitudes of more than 65 miles (100 km) above Earth, high enough to see the curvature of the planet set against the blackness of space.