The only people that seem to have much use for SMGs are bodyguards for high-profile people - that can't be hauling around ARs. The Secret Service, for instance, with the P90. It's not superior to 5.56, but it's smaller, easier to carry when they're walking around behind the president. Also penetrates armor. I seem to recall Uzis popping out when Hinckley shot Reagan.I still ask why?