General question about the goal of models in self-coaching and coaching others

Hi, This is my 2nd month with SCS. I am already learning to identify and challenge my thoughts/feelings in my head without having to go through writing out the models. But when I actually go through the exercise of doing the entire model, I still have technical difficulty, for example determining whether something is an A or R, or discerning whether something like Acceptance is an F or A.

Needing a little clarification on the goal of writing out models and when to do them.

Is it simply a structure for teaching us how to think through our reactions to circumstances with the goal of ultimately processing it in our heads (as I seem to now be doing)? Or, maybe we should practice it with each thought that makes us feel badly about ourselves, even if we are effectively able to turn the thought around, for practice sake?

Or, Is it something we do only when we are stuck with a certain thought/feeling, as writing it down helps to process the circumstance?

Thank you!