Sure. However, IMO it's more useful to look at it from this standpoint: Most usage of energy has to go through a thermal->mechanical energy conversion step.

Sure. However, IMO it's more useful to look at it from this standpoint: Most usage of energy has to go through a thermal->mechanical energy conversion step. Carnot efficiency practically limits this to 20-60% efficiency or so. In general, the smaller the engine, the worse the efficiency. If your energy input is electricity, this conversion has already happened at the power plant. If your energy input is gasoline, it happens in the car. It's sort of like comparing your salary pre-tax vs. post-tax if the tax rate is 70%. There's a big difference. Most of the other energy conversions like electrical->mechanical, mechanical->electrical, electrical->battery or battery->electrical can be done at 90%+ efficiency.