Ahhhhh, dang it. I didn't explain good
It would only apply to ship that you control (dedicated target thingy). And only ONE ship can be marked as dedicated target, so if you have one marked and you click on other one first one isn't dedicated target any more and second is. Point of all of this is simply focusing fire. I don't like to pause game take manual control on my, let say, broad side big guns and aim ship that i want to be shoot at. I would like to mark that ship and let AI shoot (AI that controls weapon on ship that i fly, to be precise
him so i can dodge missiles, raise shields or lower it, etc.
As for PD weapons i see them firing on ships with little effect pumping flux for nothing. That's i would like to put them on "shoot only missiles and fighters/bombers" command but with hot key possibility to switch it off mid battle and turn it on again if there is need for it and so on.