This is interesting to see someone post on this subject. I have been toying around with the idea of getting a 37mm grenade launcher so that I can shoot smoke grenades for cover and concealment reasons in addition to getting some parachute illumination flares.
When I was in the military we used smoke for many different reasons above cover/concealment. Signaling for shift of fire, signaling to incoming groups (I am tossing smoke: Copy, I see the _____ color smoke: Copy, ______ color smoke.), etc. Even if I had to shoot out 3 or 4 to match the volume of military grenades it would be worth it if they were needed.