I Find it quite easy to believe that it would improve thermal performance actually. To put it in a way everyone can understand: When you get out of the shower and still have water on you then you feel cold if you catch a bit of a breeze right?o) This is because the water wicks the heat away from your skin and passes it into the air more efficiently than from skin to air.
I can see this principle working on the coating on the heatsinks
Also @richie, there are desert tribes that wear black robes
That effect only works because the water is evaporating, the additional energy required to cause a phase change is taken from your body so you feel cold. Since the paint is dry when the heatsink is in use it cannot be this effect.
