I could see it being something worthwhile if it was easily attached to their existing registers. In small stores/bars/restaurants where you only have 2-3 employees max, I could see it being great. However in anything larger, it's quite a bit of overhead.

Are the employee's supposed to have their own smart phones? Alot of employees at places like restaurants, may not want to spend money on a smartphone because they make just over minimum wage. Most smartphones are going to be almost a full 2week paycheck. Alot of them have them, sure, but you're talking about a requirement now and that makes things different.

Is the business supposed to supply them? The store has to put up a huge investment in something that's not even stable yet when they already have a proven register system that works well and is widely used.

Once again, with alot of these new things with bitcoins:
Is it cool? Yes, absolutely.
Do I wish it would take off? Of course.
Is it going to happen, with the present implementation? Not a chance.

Now, one of the steps for bitcoin to succeed, is to be widely used and widely known. To be widely known, people have to know about it. If the small businesses out there, who are Bitcoin enthusiasts, start picking up these systems, then it could potentially lead to the spread of Bitcoin. If you're a small business and own a smartphone, then there is really no reason not to.