Driller (JP) made the initial post. He has modded everything else on that car and seems to be in search of nothing but speed. It's not his daily driver. The paint on the hood isn't fubared, but it's not pristine either. I would say he'd benefit more from letting the heat escape than he would be protecting the paint with the insulation.
I question the ability for the insulation to protect the paint at all, actually, but I don't have the specifications for the paint, the insulation, or the hood material, so I don't plan to do the math. In anything but stop and go traffic, that insulation isn't doing anything for the paint, and i'm not sure it even helps in stop and go traffic.
My bet is that the paint is there to reduce noise and eliminate the need to properly finish the bottom of the hood.
I think it's likely that the paint gets hotter from sitting in the sun all day on a hot day than it ever does from radiated heat from the engine compartment.