Like the title says, an option to start vehicles off, so you have to start them yourself. For realism.
I'd be fine with it if it were an option which could be toggled on or off. If it were forced, though, it would be annoying.
We already have options to start the engines heated up and there is no negative impacts to having them cold. In fact if your engine overheats through hard driving you shouldn't drive with the engine pre-heated. Anotehr realistic useless feature wouldn't be unwelcomed.
Supposedly? Maybe its because i always keep the torque curve and not any other form of telemetry, but i never noticed that.