Hmmm, on second thought, this has the problem of double-spend, so perhaps it's not so simple. I suppose there really is no way around this problem of transfer-speed without using a trusted third-party.
Bitcoin is much faster than other transfer methods - paypal creates the illusion of immediate transfer, but they can reverse the transfer anytime within 90 days. ie a 100% confirmed paypal transaction takes 90 days.
To all intents and purposes Bitcoin transactions are immediate - a zero confirmation transaction on the bitcoin network is safer than any credit card or paypal transaction (from the merchants perspective).
For small amounts the economic risk taken by the merchant is much less than that of anyone accepting credit cards. If they are afraid of double spends they will price their product to account for the risk.
Edit - If the price of an item at POS is the same in bitcoins and $, then the saving in credit card fees more than offsets the danger of double spend (for small value transactions)
