@Andy210 The defeats the point of sexual reproduction, which is to introduce genetic diversity into offspring, which would increase the chance of a species's survival in different conditions. Asexual reproduction carries a high risk of mutation and that offspring will show similar phenotypes to that of incest in sexually reproducing animals.
That and having that kind of body is just not ergononmic and minimizes the benefits of human anatomy in favor of becoming a strange ball creature that scuttles around like a spider. It would litter ally be out competed by anything