I have no idea why they want this. I know of a few more schools that request this as well. They said during our interview that it wasn't someting that would affect us negatively. They weren't going to take back our acceptance, but they needed it before we started.
I am thinking maybe they look at them to see if an applicant is in finacial trouble and if so their financial aid department can work with the student to see about low interest lows or something. Only my guess, I really don't know why.