The Arizona State University states the obvious: interns have better employment outlook. This blog certainly doesn’t question this assertion: it’s even the basis of the unfairness. If working for free gives you a leg up, it cancels the argument that students have the choice to take the internship or not.
This being said, make sure your future employer doesn’t question your value if all previous employers did not see the point of paying for your services. Accept only fair internships.