I have to agree to a point. The 986 didn't have the hip flares that the 987 got where such a protection makes sense. I can, however, imagine that it would see good use for track days and AXs, should any debris get kicked up or you clip a cone with the rear quarter of the car. Not likely to happen often to most people, but it'll sure come in handy that one time you need it and it's there...kinda like your insurance.
If your reason for getting them is for those times that you'll be on a track and you're one of those that goes fairly often, I think it's a worthwhile investment, looking at it from a stance of function over appearance.