That's the problem this is really not a 'commodity' or even a 'currency'..... its a collectible that people are trying to use as a commodity and currency.
Just like any other collectible it has value and its value is based on what someone will pay for it.
I would say it is a commodity, a currency and a collectible. with bitcoin you can do anything you can do with money and more. Collect it, speculate with it, use it for purchases, whatever.