Over the long term, lots of assets are better investments than cash. That's not what I'm getting at. If I go to the store and prices are in dollars and not Bitcoins, or if loan payments can't reasonably be priced in Bitcoins, they aren't performing one of the primary functions of money.
Put it this way: people are excited because the price of Bitcoins in dollars is going up. If things were priced in Bitcoins then it wouldn't make any difference - the prices would still be the same (in Bitcoins).
