Its not just the headlight harness, its the whole harness for the front of the car including the washer fluid pumps, horn, and radiator fan. It has to go across the front of the car somewhere. If you're tucking it, it can either go underneath the top of the rad support, behind the bumper support, or down along the bottom of the frame. Anywhere else it will be visible through the grills. Where do you route it when you tuck your harness?Why would your headlight harness need to go across the front of the car? Seems pointless. Just a bunch of extra wire
The main thing I'm worried about is water/road grime, but I put the bumper on and it is nicely concealed by the part of the bumper below the grill.
As far as easy to access, I'm not super concerned. When you're tucking wires, you have to give up some of the practicality. I'll just make sure all the wiring is done right the first time and I shouldn't need to access it.