With bitcoin at around the $US10,000 mark and Coinbase, the bitcoin exchange, boasting more accounts than brokerage Charles Schwab, some preemptive consolation and advice are in order for people who stand to lose lots of money in a crash. First the consolation: Even if that money goes up in smoke, the investment will have helped make the world a better place. And the advice: There's a way to profit from that too, by making side bets on other applications of the technology that powers bitcoin.

That's also the case with other unprofitable projects that are losing the investors a lot of money and may lose more in the future: Tesla, Snap, Uber. Investments in them may never pay off -- or may only pay off for those who cash out at the right moment, like lucky investors in a Ponzi scheme. But they pay for humanity's important advances, and for progress in entire markets.

Techcrunch columnist Jon Evans, writes that unless you're an investor in the electric car company, Tesla's purpose, as far as you're concerned, is not necessarily to make money but "to pioneer fleets of smart mass-market electric cars, and the infrastructure to support them, and battery technology which is not limited to cars." He draws an analogy with the Channel Tunnel between the UK and France -- a disaster for its private investors but a success as a much-used piece of infrastructure. The billions plowed by cities into Olympic preparations can also be useful in that way: The housing and sports facilities for city dwellers wouldn't have been built otherwise.

This seems like a socialist argument: Who cares about a bunch of fat cat investors losing a bit of their enormous wealth if the projects they fund are useful for society? Essentially, however, a market-driven, capitalist mechanism is at work. It's competitive and based on the concept of the hype cycle, used by Gartner Group, a US tech consultancy and research company, to describe how promising technologies get overhyped at first and then proceed from the "peak of inflated expectations" through the "trough of disillusionment" and up the "slope of enlightenment" to the "plateau of productivity."