Stuttering is a disability and severe stuttering can be a severe disability. Bad vision and bad hearing can also be disabilities but eye glasses and hearing aids often ameliorate the negative effects. A stuttering prosthetic can often ameliorate the negative effects of stuttering. Is it temporary? Is it a rip off? According to reports, the positive effects can be permanent. Just because a professor makes a pronouncement does not mean it is accurate. How do we determine if something is positive or negative? Try it. Try it long term. See if it works. That is called SCIENCE.