On a totally unrelated subject, nitrocellulose finishes on guitars are sought after as opposed to poly finishes, and are preferred by some artists for the idea that they let the wood "breathe". So some finishes can have certain characteristics attributed to them, but for a speaker where the cabinet is supposed to be sonically transparent, I think they're reaching a bit with their claims.
Unbelievable
Yamaha really made this statement:
Glossy black piano finish provides improved signal-to-noise performance
https://europe.yamaha.com/en/products/audio_visual/speaker_systems/ns-5000/index.html
I thought I would seek opportunity to hear these speakers, but now I do not think so