Balanced designs only make sense if the headphone is extremely hard to drive and you wish to use it with a more powerful, balanced source. The idea that there is audible noise in single ended mode for short wire runs is actually false. So if anybody is going through the effort of making this balanced thinking they will be improving the sound by eliminating audible noise, not a chance of that happening.
Lets just exaggerate things completely and pretend that there is as much as 1% extra noise with a single ended design. What is it you do with a headphone? You listen to music don't you? So if you are listening to music, that means 99% of the signal is going to be music. Do you think you can possibly hear 1% noise through the 99% music? And keep in mind, whatever difference in noise that exists comparing single ended to balanced in such very, very short wire runs is well less than 1%. How on earth do people think they can hear such small differences?
Balanced runs of cable make a difference over very long distances, like in recording studios or stadiums. These really short wire lengths we encounter in personal audio just don't suffer from any audible effects single ended.
If people like to tinker and enjoy the challenge of doing things simply to do them, that is a perfectly good reason to do so. I think if I had the time and the equipment I would probably very much enjoy such things as well. I only post this as the false notion of the advantage of balanced versus single ended topology in personal audio is so darn persistent. Just because you can measure a tiny difference does not at all mean you can hear it. Those are very different things.