I want to pick some of the limitations that cryptocurrencies presently face. For example, the fact that one’s digital fortune can be erased by a computer crash, or that a virtual vault may be ransacked by a hacker. It may be overcome in time through technological advances. What will be harder to surmount is the basic paradox that bedevils cryptocurrencies: the more popular they become, the more regulation and government scrutiny they are likely to attract, which erodes the fundamental premise for their existence.