I wouldn’t say placebo. It’s definitely doing something.
I would say this is still a placebo. Placebos always still do something. A sugar pill tastes sweet and modifies the sugar levels in your blood. The important questions are validity and effectiveness, not whether or not it does something.
Balanced audio will not eliminate noise in most of the circumstances where a headphone user hears noise. There are far more likely sources (the source file itself, DAC limitations, audio amp limitations, external sound from their environment, etc). It will help in some very specific circumstances, but that's like trying to sell snow chains to all car owners on the planet because you can claim that they improve traction.
If you do work in an environment where changing to balanced headphone signalling helps... why are you working with your head inside an RF hazard zone?
(From page): However, balanced audio does a better job of eliminating noise, should it exist in your signal. In a case where extraneous noise is present
Misleading.
Noise exists in all signals. Balanced audio only "does a better job" in circumstances other than what this product is being sold for. Discussing this at all gives it false merit anyway.
EDIT: Giving this some further thought: balanced and unbalanced signalling is mostly moot when you're an isolated device with one cable attached. From an RF standpoint you're not forming both halves of an antenna (dipole or monopole+ground). Electrically they both look extremely similar in this scenario. Your partially conductive human arms waving around will probably couple to RF noise better than the headphone cable.