You are indeed correct but that is not how you run and sustain a route. Yes you are more likely to get awareness of your route from MAN over BHX, but with the amount of competition, this will guarantee that yields are limited in order to beat your competitor.
To my eye, the opportunity for Primera at MAN is European sun sector in the void left by Monarch, Vueling and Norwegian, and not the TATL sector which at MAN is saturated.
That's not to say they will get an easy ride at BHX. The true sign will be the summer 19 schedule!