Board Thread:Speculation House/@comment-24772070-20161204040824/@comment-25396609-20161209005828

Think of it this way; aura absorbs damage, the reason you take a noticeable dent to your aura when your body is hit is that flesh is, all things consider, really damned easily damaged.

Metal, ballistic plastics, ceramics, and the like which weapons tend to be built out of are harder or otherwise more resilient than meat; meaning aura doesn't have to do as much to soak damage.

It is, presumably, the same reason people wear armor despite aura acting like an overshield.