Internships are great while in Graduate School.
I do not how much they actually are allowed to do before reaching this level. And they have to be baby-sitted (looked over).
But say at Med. School (Law School, other Grad.), medical students can actually provide a real help and they do, while getting very rich training themselves and being greatly appreciated by those who they help as well as their superiors. And this trips are expensive, but usually are selective as more want to participate than spot available.