Producing the extra weight of the seat heater requires extra fuel to burn. Now multiply that by the number of cars on the road. Will cost the customer a (small) amount extra in fuel costs for a part that is not being used. So there is an economic argument that ya, we can subsidize manufactures by taxing people more. Seems like a bad deal to me.
Now lets talk about CO2 output of driving around extra dead weight. Makes it worse.
Now lets talk about CO2 output of driving around extra dead weight. Makes it worse.