Many of them do, yeah - a lot of licensed professions require practice hours to qualify, so cheap/free service from people doing their practical study portion can be found if you know where. One of the main downsides (aside from the bit about getting your medical care from somebody who, by definition, doesn't have a lot of experience) is you don't often get continuity of care. When your student-practitioner finishes their semester or two of practice hours they move on, and if you still need care at that point you get to start again with a new student.