I saw those, but I always worry about metallic cases. If you try to puncture a plastic/rubber case, like the Otter, it cracks and squishes. If you do so to aluminum, it bends. I'm not so sure the extra durability is worth the risk of a permanent puncture continuing to put pressure on the device between impact and case removal.

Kind of like cars or houses with plastic panels/siding vs aluminum. Plastic self-repairs more often, where the metal version just dents...