I think it's an open question as to whether that belief can sustain a meaningfully high Bitcoin price. There has never been a currency or asset that has been so easily tradable among every person in the world (even among anonymous people). ...

There are about 20 million bitcoin wallets, which surely overstates the number of users since a lot of people have multiple wallets, and a lot of old wallets are lost. There are about 30 million merchants who accept Mastercard and Visa, which I think significantly understates the number people you can pay. Paypal has about 200 million users worldwide, all of whom can pay each other, and all of whom can take payments from any of the billion people with a Mastercard, Visa, or Amex card. Credit card payments aren't free, but they usually cost a lot less than $50.

For fans of anonymous payments, there are 300 million people here in the US who are happy to accept anonymous US dollar cash, and a billion each elsewhere who welcome rupees or renminbi. People who prefer electronic payments can look to Tencent, the company that runs the wildly successful Wechat online service. If you're in the U.S., you've probably never heard of it, but it has over 900 million active users, mostly in China, and Wechat does payments.

I am envisioning the Bitcoin Apocalypse. Fiat currencies (that's a term of art for what we'd call money) have all hyperinflated to infinity, people are hunkered down in their hilltop redoubts, and firefights over a case of beans are not uncommon. Nonetheless, the power's still on, the networks are still connected, the switches and routers are still switching and routing, so Bitcoin and its clones still work. Whew!