I'm aware of that. But using those terms is somewhat misleading - modern vehicles use a monocoque chassis, and these castings will be in areas which are routinely damaged in collisions where panels can currently be replaced/repaired by any competent bodyshop. You can usually buy such sections individually, unpick the originals and replace with new ones, returning the vehicle to as-new condition - even when you're a DIY mechanic with suitable equipment.

That won't be the case with castings, and even less so with Tesla given their approach to third-party repairs.