Hi Ryan,
I agree, winter is where this can help, The LG can keep a 7-8 gallon container over 55 in a 35 degree room with 9 watts but you are correct in your prediction with the wattage, with a regular heat source 9 watts would not be sufficient. Soil is quite a good insulater so its hard to warm, the heat dries the area where it meets the soil and dries it out, the dry soil becomes even more of a barrier for moving the temperature.

The efficiency here comes from mixing the heat with the moisture this creates a much more efficient way to move the heat through the pot which is why we can use lower wattages. Using a good mulch or thin foam will also help in extreem conditions.
thanks for the comment
Mark