I never thought about this, can you steal cars by lifting them like that in the air? Not that I think that will happen, but it would be really funny to hack such a robot and just collect cars around

This technique is frequently used by towing companies impounding cars and reposession agents collecting cars for loan defaults - absolutely you can pick up and take a car away with the right hardware.

Just for most people a stolen locked car isn’t really of much uses.

Yes. If you can get under it.