Both serve the same purpose, to protect the surface and to keep it from being shiny.
My 2 cents: Be very VERY careful when clear coating any of your armor. Do NOT spray it on too thick. Make sure to apply several thin coats. If you spray it on too thick, and the coat begins too cure, it will contract and crack your paint. As it dries it begins to pull together causing your paint to flake. Maybe just a little at first, but by then it's too late and you will regret not taking your time with the process.
I learned this the hard way and had to repaint several pieces of my armor.
On the plus side, it is an effective way to get a "cracked" look but it is very uncontrollable.