It helps but it’ll still be hot as crap inside. You just won’t need your oven mitts to grab the wheel.

It’s not. It’s designed to be inside as a sun reflector. People just use them to block ice formation too but they won’t last as long that way. They weren’t designed to be rained/snowed on and frozen…but they aren’t expensive so does it really matter?

Deterrent for when someone jams a flathead screwdriver in your ignition and starts the car you still can’t really drive anywhere because you can’t turn. Remember this was before expensive NFC or radio car keys.