Besides all the positive reasons above, it should be pointed out that the integrated brake controller is part of the traction control system. If steering or braking get pushed to their limits, the on-board computer uses the integrated brake controller to help get things back from their limits. When I read this in our 2009 3/4 ton suburban manual, I was sold. I made sure to have this in our duramax. Besides, the less stuff I have near my knees (brake controller box), the less damage I can do.
2012 GMC 3500 Duramax Crew Cab, SuperGlide 20k
2014 Cedar Creek 36B4, LP Onan, Level-Up, Trail-Air pin, electric fridge