Writers’ Notebooks are an essential piece in well-rounded writing programs. But, organizinging and using them appropriately is not intuitive. In fact, unless you use one yourself regularly, then it’s quite a difficult thing to teach.
I believe anyone teaching writing to students, regardless of the grade you teach, should be a writer in their own life in order to teach writing well. That’s a tall order in our busy lives, and for many teachers it may seem unrealistic. I get that. In fact, I’ve been there. But you really do write all the time. You just aren’t collecting it all into a notebook.