However, it fails to use bitcoin as a currency in the sense that other stores use dollars as a currency. The prices on Silkroad are adjusted to mirror the USD->BTC exchange rate dialy. And, I would suspect that the majority of the users are buying bitcoins to buy goods on Silkroad, and that venders on Silkroad turn their BTC back into USD often. These two use cases don't support BTC as a viable currency. It is being used exactly as detractors presumed: merely a way to launder money.