While I do believe encouraging local businesses to accept bit coins may have future advantages, I can see why there might be some risks involved with this. The price of the bitcoin to the dollar is extremely volatile, and this may cause some problems for local retailers who may not know the currency exchange. I'm not quite sure what the potential economic impacts of this would be, but if there is someone here with a greater understanding of economics, I'd gladly hear your input.
First thing, I don't know someone that use bitcoin but do not know of currency exchange. Local businesses don't even know about bitcoins, that's the only reason why they don't accept bitcoins. And even if they do, there will only be a few people that would risk their money or their business's money since bitcoin is volatile. It's basically the same with normal bitcoin users. There are some that are too afraid to risk it so they don't use bitcoins at all. Others use bitcoin but convert their coins to fiat right away.
Bitcoin is for risk takers, that's why. But honestly, with what bitcoin is going, those that have been accepting bitcoins as payment before and haven't converted yet, they already have made tons of money from holding bitcoin alone.