I also think that it's not a placebo. I have a few cables of mine re-terminated as 3.5 TRRS. The improvement in sound quality is very surprising, although we need to keep in mind that this could also be due to the quality of new plugs (I use Oyaide rhodium 3.5 TRRS plug). Instrument separation becomes a lot better. Imaging also improves. Specifically it becomes deeper but not wider (which is a huge different effect from 2.5 balance as 2.5 balance tends to improves soundstage width). I would say that overall the improvement is very rewarding. The only issue that marks a major difference from typical 2.5 balance and 4.4 balance is the absence of improvement in driving power.