You could have done a much better job explaining what Bitcoin is haha. But who am I to criticize? At least you are talking to merchants about Bitcoin 
I would argue it would be more effective if the person were to look it up himself instead of forcing him to hear about it when he probably has a line of people to "ring up"With that being said I would find it very unlikely that the cashier at a retail outlet will have any influence as to what payment methods the store chain accepts.