Checkboard, the option is not to add heating to LE devices, but to inhibit the heating of the leading edge of the wing when the leading edge flaps are extended.
When deployed, the LEDs move up and in front of the wing leading edge. Some of them have a small air gap for air to flow between them and the wing, but others don't(if I remember correctly there is a rubber seal on the back of them which actually contacts the wing, allowing no air flow. Without cooling airflow, the LE's might get a bit hot. I've seen what happens when the heat is not inhibited on the ground, the metal wing leading edges buckle.
Rgds
NSEU