Art is what it is. Artists are attracted to different materials. I like using bones, teeth and hair. I have used bones and claws and horsehair and leather (which along with rawhide IS skin) in my work. I also love skulls.
If you aren't too squeamish and would like to see even more animal part art check out this site. http://www.morbidtendencies.com/
She doesn't kill anything to get her material. How many of you objecting to the skin wear leather and eat meat? Or own predatory carnivores (dogs, cats, snakes) as pets?
The use of animal parts as design elements is very common in American Indian craft and costume. An artist coming from just such a tradition would not find it unusual or gross.
Personally, I was more freaked out by the fingernails.