I wouldn’t say placebo. It’s definitely doing something. I would say it’s unnecessary in most environments, and probably definitely on a mobile phone. But to lift right out of the article:
You may be wondering if balanced audio is “higher quality” than unbalanced — the answer is no. Balanced cabling doesn’t provide a better quality of sound than unbalanced cables. Audio source and the quality of materials in the actual cable’s construction determine sound quality more than anything. However, balanced audio does a better job of eliminating noise, should it exist in your signal. In a case where extraneous noise is present, balanced audio will be clearer than unbalanced audio.