Of course it serves a design purpose! With the line mounted in this bracket, the hose will not twist or tangle with anything over the complete range of suspension movement and steering angle. It also allows a different bracket to be used for the larger trucks, or COE's, etc. with different suspensions. If you replace it with something else, be sure your location guarantees the same. If you don't have stock suspension, the stock bracket location may not be correct.
E-Dawgie, I would think that the design was to make it easier for assembly at the factory. Maybe the lines could be started and tightened quicker while the frame was traveling down the rail. Just a guess tho !!! I took mine out and used a different (tab) on my front when I re-plumbed it for disc brakes. They do look a bit strange if left there when you clean up the chassis. I like bulkheads anyway..