Using Drylok on exterior wall

I have a free standing brick wall (on the driveway, not part of the dwelling) that was recently plastered with stucco. In order to give it a smoother look, I used Drylok on the top and only one side of it so far and did a good job on filling and hiding some of the minor imperfections in the finish. There is still another side of this low wall that is still bare and now I am reconsidering the idea of using drylok on the simple fact that it might not let the wall breath.

Is this something I should be worried about given the free standing design of this wall? Isn't "block filler" similar to drylok? What else could I use here before I start painting this wall?