I am of the opinion that they will work in the same way any other partial exercise will, whether it be shrugs, rack pulls, squat lockouts, high board presses etc - it adds a shitload of mass where you want it, activates everything and gets you used to heavy ass weights.
I remember Jamie Lewis saying that whenever he drops squat partials and deadlifts out from his routine he always loses mass and he does them with fucking crazy weights - over 10 plates a side