The advanages to a mech is speed, better terain ability and a more steay barrel. Funny how we built these rock crawlers and tanks and then you watch the camera men run into possition on top of a hill to show exactly what the think can climb. Put spikes on its feet and it could run up a glacier. If the torso could move up and down to steady the barrel you also could have a more acurate fire control. You are right about the low siloette but a tank cannot crouch behind a hill. pop up for a second and crank a round off before hiding again. They just do not have the tech for the engine and gyro control yet. It will come.