Out of respect for your students and the profession of flight instructing you should only get a FI license you want to instruct.
Yes, you get the hours and the experience, but there is nothing worse than an instructor who merely goes through the motion of teaching while dreaming of a seat in a jet.
I taught for a few years and my goal was to get a jet seat, but I loved teaching, still teach, and take it very seriously. Unfortunately, I have seen instructors who hated instructing and it reflected in their work.
As poina said, there is no better way to get to know a subject than to teach it to others. If you spend time with students you will definitely learn something in return.