If you're not a math genius or a cryptographer, it can be hard to wrap your head around what Bitcoin is. So two years ago, I decided to get familiarized by immersing myself in it. I got rid of my cash and credit cards, and spent a week in San Francisco living on Bitcoin. At the time, few people had heard of the cryptocurrency, and fewer actually accepted it. I couldn't pay my rent. I had to walk or bike everywhere. The only food places that took it were a sushi restaurant, a cupcake shop, and a grocery store, which were all miles away (I lost 5 pounds in a week). It was hard, but I got to know the fervent libertarians, entrepreneurs, cryptogeeks, and fringe economists who were part of Bitcoin's then-small community. They so desperately wanted their radical currency to succeed, and they were worried at the time that the U.S. government might ban it.

A year later, in 2014, I repeated the experiment and had a completely different experience. Venture capitalists had discovered Bitcoin, pouring money into startups that made it easier to use. Intense interest from China sent Bitcoin's value over $1,000, minting many of those early cryptogeeks into multimillionaires, at least on digital paper.