My vote is yes too. Agreed with everyone above. My issue is that water can get on the hot sides of my twins and they will rust. Wish I would have coated mine.
It wouldn't hurt you if you don't want to spend the money. Heat transfer is inversely proportional to thickness of material. Ceramic coatings are quite thin so the amount of heat transfer they reduce is rather small. If I was building an all out race car or was really concerned with looks I would consider it. For my money Ill live with a little rust and just build heat shields.