How about mortar smoke, how can I use it to help my offensive/defensive maneuvers?
Offensively, you can use it on an enemy elephant or su85, so your units (tanks, atgs) can get close without being fired upon. Also, on a slow unit like an elephant you can use attack ground from a distance into the smoke to damage it safely.
In infantry combat you can use it to help you flank of course. Or do a smoke barrage on a patch of deep snow to protect your infantry while its slowly moving through the snow into the action.
Defensively, you can use smoke on the retreat path of your units to protect them. For example, your tank gets a damaged engine and an enemy atg pops up. Do a smoke barrage just behind your reversing tank (to compensate for the delay) to protect it from the atg.