The watt input between a bulb and a heater may be similar, but the
efficiency of heat transfer is related to surface area that can
radiate. A bulb has a tiny area compared to the surface area of an
electric heater and in a finite time will distribute its heat energy
less efficiently than a larger surface area heater.
In an infinite time span in a closed environment, the bulb and heater
will achieve almost a similar heat distribution. Since we don't have
infinite or even long time spans, a large surface area heater wins
everytime.