Look at where the gun is pointed when sitting using that carry location. Lots of important (to most of us anyways) stuff AND the femoral arteries. If I'm going to shoot myself, I'd rather shoot myself in the butt cheek than the ,well you know. A pistol carried behind or on the hipbone is less likely to cause a life threatening unjury in case of an ND.
My Son showed me a set of internet pics of the results of a poor/wornout IWB holster design and a Glock. Fortunately, it was behind the hip and the guy only had some vehicle damage and a scrape on his butt. Had it been in front of the hipbone(appendix carry), it's a good chance the guy would have had serious injuries or worse.