After a volatile week, a bitcoin was still worth about $40,000 on Friday. That is still quite valuable, something bitcoin enthusiasts have been eager to point out.

There is nothing in the code that governs the cryptocurrency, however, that provides an answer to the question: How can bitcoin become money if it becomes so valuable that you don’t want to spend it?

It is certainly true that even with this week’s drop, over the long run the value of a bitcoin has appreciated. In 2008, it was nothing more than a PDF that contained an idea. The PDF traded at a spot price of zero, considerably lower than current levels. That’s an impressive 13-year performance for any asset. It is an Amazon or Apple level shoulda-got-in-on-the-ground-floor performance. I first had bitcoin explained to me by a group of Swedish hackers in an attic in Malm? in 2011 and let me tell you: I have regrets.