I gained a lot of professional experience (i.e. how to work/communicate in an office/business setting), financial modeling experience, and enhanced my ability to multitask.
What I wish was different
Sometimes there was a lot of slow work or no work, so I was sitting on my hands for maybe 2 hours a day on average.
Advice
Ask as many questions as possible. The mortgage banking/lending industry is extremely niche so the more questions you ask during your internship, the more you will learn/get out of it.