[smosher]

Well, you could say the exact same about every currency.

There is an online market (of goods) built around BTC because of its particular properties. This market wouldn't exist without it. You can't sub in barter or gold or most other forms of money, and especially not anything that leaves a record.

The nonsense argument about BTC being a fiat currency is confused. There is an authority in a sense that dictates the mechanics (but I see it much like the 'rules' for determining what is and isn't gold.) However there is no authority that confers value of any kind to the currency.