The inconvenience is when you have to manually hold open the barrels in order to load as opposed to let gravity due the work. I have heard this argument before about this was design intent to keep shells from falling out when carried open. I don't know about everyone else but when my gun is open the barrels are pointed down and the shells will not fall out due to the laws of gravity. I can't think of a scenario where the gun would be open and the barrels would be pointed in such an angle (when loaded) the shells would fall out.
