Yes so? I'd rather want that 30% energy to be converted to kinetic energy, than 0% energy being converted. What's the point of using a car as an immobile heater

Yes so? I'd rather want that 30% energy to be converted to kinetic energy, than 0% energy being converted. What's the point of using a car as an immobile heater? I'll turn on the heater once I'm on the highway, not before.