Writing elected representatives: strategy question

I recently wrote letters to two of my senators, and received responses in return. Setting aside the question of whether it was worth writing the letters to begin with, is it worth writing a follow-up letter responding to points made in their responses? Obviously, I'm not going to persuade either of these senators to change their mind, but is it worth the exercise of writing a follow-up just to emphasize that there are people they represent who hold my views, or is it largely a waste of energy? Is it simply delusional to attempt to engage in this sort of debate with the office of an elected representative whose fundamental politics are at odds with my own?