In my target shooting to killing experience, I like to know where bones are that are going to interfere with my bullet path or arrow. I understand that the targets can be to busy but it is nice to know where my shot is headed under the skin. Especially if I do not have a clean shot. I like the target you shown though. Simple and to the point, you hit here they go down.
I hope I am not coming off argumentative. That is just my opinion on why I like to have some targets with the skeleton.