I am not an airline pilot (yet), but I do fly heavy jets for the military. Being an aircraft commander in our case means teaching the young up and coming copilots to fly the plane and manage the cockpit and crew. You do it by nature whether you are an instructor pilot or not. I would imagine it is pretty similar in the airline industry.
I learn something from just about everyone that I fly with, junior, senior, or peer. Good CRM = instructing.
Being a CFI is going to teach you a lot about managing a student, flying, and multitasking in general. It is a good foundation that is an important part of what you are going to do for the rest of your aviation career.