Medical schools pride themselves on being professional schools, and not graduate schools. They understand that they cannot train new doctors, without giving them exposure to actual medical practice. Law schools are finally moving more and more to the professional school model, by offering experiential learning, including clinics.
I have become a big believer in clinical education, and the impact it has on students, as well as the clients they serve. Students and alumni regularly tell me that their experience serving in a clinic was the most rewarding and valuable thing they did in law school. Some student testimonials can be found here.