I don't think OP is talking about the aerodynamics. It is about the vehicles' effect in a collision. Most automobile exteriors are designed to absorb the energy of a collision by crumpling and protect the interior. The Cybertruck's use of work hardened steel in its exterior would cause it to either transfer most of the energy to the other colliding vehicle or in case of collision with a large stationary object like a concrete wall transfer the energy to the interior.