Except you will never use a 15-ft cable for headphones, so balanced interconnects and EM noise rejection are beside the point here.
“Balanced” on headphones is completely different, it’s about eliminating the common ground and getting better stereo performance. Can Someone Explain Balanced to me? - #6 by abm0
This is why IEMs are the first to benefit from it: they have such low impedance it’s close to the common-ground impedance of single-ended cables, which leads to high L-R crosstalk and a somewhat constricted stereo image. You switch that to balanced and you can easily hear a difference in the stereo separation.