Bitcoin is only a commodity in the sense that its backed by its ability to be transferred across the internet easily, anonymously, cheaply and securely; better than any other currency. One would usually define this as money but it could also be said that money is a commodity backed by the same use.
A logical answer seems to be that money is a commodity.
The process of transfering funds around the Internet is a
service that the bitcoin network performs with near zero cost, but that service is neither an inherent feature of the currency that is bitcoin, nor is it possible for a service to also be a consumable with an alternative use than it's monetary intent.
Thus, back as square one. Bitcoin is a currency, and only a currency, because it's
intended to be used as such and cannot serve in any other capacity.
And the words money and currency are
not interchangable.
To call bitcoin a currency is debatable what if everyone used Bitcoins as a representation of stocks of ownership and each address what to show the amount of Stocks each person held. I dunno just throwing it out there that I think bitcoin is just "Bitcoin" and its so new and crazy idea that nobody knows what it is or what potential we can do with it. But all i know is if we classify it, we could possibly restrict our selves to future uses if we Define Bitcoins as anything other then a Bitcoin.