Right, the trust in the future spending power makes a currency not only a medium of exchange, but a medium of store.
It seems that as far as alternative currencies are concerned, altcoins have a better chance of being spread. What's to prevent Amazon from coming up with AmazonCoin, pre-mining an entire AmazonCoin set for themselves, and then offer this altcoin with a liquidity guarantee on largest retail site. Nothing to prevent them from accepting BTC, but I think any US retailer would be prone to quickly trade in BTC for USD after the transaction is completed, as there's volatility risk, and payments to merchants and the tax man are due in USD anyways.
It seems that as far as alternative currencies are concerned, altcoins have a better chance of being spread. What's to prevent Amazon from coming up with AmazonCoin, pre-mining an entire AmazonCoin set for themselves, and then offer this altcoin with a liquidity guarantee on largest retail site. Nothing to prevent them from accepting BTC, but I think any US retailer would be prone to quickly trade in BTC for USD after the transaction is completed, as there's volatility risk, and payments to merchants and the tax man are due in USD anyways.