Understanding the entire Film Process is VITAL.
Specializing 'is' important. But knowing the entire visual effects pipeline inside out is critical for growth in an artist's career.
Those who can just do their job, and make a set of sparks or an explosion - are good.. But the Artists who can take the entire production shot through to completion are Rockstars!
This is called taking the ball and running with it - rather than just be someone who adds little elements to a shot, You're trusted in making it YOUR SHOT and you're able to influence and tell the story of what happens in that exact moment. The shot or sequence becomes 'your baby', by you taking ownership.
These are the ones that go on to be supervisors, that have job stability, who get to pick their projects, what they want to do, where they want to go.. Who stand out.
Understanding lighting is a critical component to making any shot look good and understanding how to integrate CG elements into live action shots, and to have true compositing knowledge to transform a shot from 'mediocre' to 'not only amazing' - But FINAL.
The more you understand about the Visual Effects process, the better grounded and the more vital you are to the team.