The author makes valid points, but the fatal flaw of the argument is the critique comes from the persoective of a US based investor.

One needs to realize that bitcoin is a truly global currency that does not care about borders. It has extremely low barriers to entry for the average participant. Just an internet connection.

For counties with stable governments, strong institutions and a stable local currency the appeal of bitcoin is more speculative.

However for people who live in countries with unstable governments, weak institutions and an unstable local currency, the appeal of bitcoin as a means of survival is immense.

If you do a google trends search on bitcoin look at the countries with the highest search activity. Many are not what you would typically expect.

So yes, speculative and ponzi like activity has played a huge part in the rise and fall of bitcoin prices. But that is true for any asset bubble that rises too far too fast. There will always be an underlying demand for bitcoin due to the fact it is the first borderless global currency. What is the appropriate price is another story.