If it is so tactically sound why do LEO and military not conceal? I am more scared of someone CC a firearm than I am someone OC a firearm. It is fairly easy to assume that a person OC a firearm properly is not a criminal, but when I see someone CC I have no idea be if they are a criminal or not because whether one chooses to believe it or not, criminals do not OC their firearms.
Those in uniform OC, because CC'ing in uniform would potentially make them a bigger target - i.e "an unarmed LEO"
off duty cops, detectives and plain clothes officers tend to cc, I assume for the tactical advantage.