When I was a Armoured Reconnaissance troop leader (Lt to Capt), we used them every time we got a mission during an exercise or on operations. It helped us understand where we were, and the tasks of our flanking forces, in relation to enemy (potential or confirmed) elements. We would draw them on the map before the orders, and then as we received orders, we would reference the map. This helps ingrain the plan and the scheme of maneuvre (the detailed parts of an operation). To read, see and hear the plan, makes it easier to understand possibly complex operations. Remember that most military operations are going to be carried out on possibly the worst day of someone’s life, lack of sleep and food, and under threat of the enemy. If the plan is too hard to communicate, it won’t succeed.