Parts of Arizona I could articulate why it might be a good idea to open carry. There is a good deal of drugs run over the border and so a stranger in a border town might not be a welcome site at times. There are also illegal immigrants crossing who might be desperate for food and shelter. That is a situation where it might be called for to display a firearm openly.
You live in a town by the border and see a stranger or car you know doesnt belong so you open carry around the property to reinforce the notion this isnt the place for their intended business.