During heating season you are correct. During cooling season you end up paying twice for the extra energy consumption of incandescents. So it ends up being climate dependent. In cold countries the savings from changing out incandescents can be a fraction of the savings obtained in hot countries. Where I live you only end up getting half the benefit you would expect from the energy savings alone. If you don't have AC here then the benefit is even lower.

There is a current internet legend that the heat from incandescent bulbs does not contribute significantly to building heating. This is entirely wrong for the obvious thermodynamic reason. It's even been tested experimentally with the result that almost all the heat from the bulbs ends up as general heating:

http://www.cmhc.ca/odpub/pdf/65830.pdf