During cold winter months, when one is otherwise attempting to add heat to the indoors, the 'waste' heat from incandescent bulbs is not really 'wasted', since it contributes slightly to maintaining the interior room temperature.
If they are resessed down lights you mostly end up heating roof or ceiling space. And in summer not only do you consumer power for heat you don't need, you end up consuming power to remove said heat with AC. Also in winter there are much more efficient ways to heat than electricity, such such as heatpumps.
