I read your blog post and it seems what you have argued makes sense. It seems like by the letter of the law (U.S. law) bitcoin is not a currency. You also argued that bitcoin is not an investment contract.
To me it seems like if bitcoin is not a currency, and if it's not security (investment contract), then is bitcoin then a commodity?
You bring up a great point, I only argued what bitcoin is not. I will focus my next post on what bitcoin is. I do not know the legal definition of "commodity" off the top of my head, but I will find out and let you know.