The fact that people talk about the "market capitalization" of bitcoins suggests that they treat it as a speculative investment and not a currency. Maybe it

The fact that people talk about the "market capitalization" of bitcoins suggests that they treat it as a speculative investment and not a currency. Maybe it is unavoidable in the adoption phase of its life (supply relatively fixed and demand fluctuating), but the price swings relative to other established currencies detract from its usefulness as a currency.