"I either needed to make friends with the monster or kill him and that I had the power to do either one."
There is a third possibility: Let it catch you. That's actually how I got rid one of my recurring nightmares. I'd swear there was a second's pause as my brain asked itself "Uh, now what?"
I now fairly frequently get some imagery in my dreams that have the capability to spark nightmares, but they pretty much never get past the very beginning phase, because my brain knows from experience nothing bad can happen. Big scary monster with teeth chasing you? The best answer is to hop right on in. Another big scary monster with teeth inside the first one? Hop right on in again. Recurring dream involving fear of heights? Just fall. Eventually it'll all work itself out.
I now fairly frequently get some imagery in my dreams that have the capability to spark nightmares, but they pretty much never get past the very beginning phase
That's pretty much how I feel as well, except I wouldn't say frequently for me. Occasionally I'll get imagery that is kind of nightmarish, but it usually doesn't seem to escalate beyond a certain point.
Facing one's fears, be they real or imagined usually has some value, in my experience.
So for me, I guess I would call that pretty life changing, but perhaps not in the way that others might think of when they attribute the term "life changing" to lucid dreams. I feel that there is some degree of mastery one acquires over one's own mind with these kinds of exercises. A feeling that this is my mind and I control it. That's always been pretty valuable to me.