On the face of it, you are right; there is no big difference what you call something. There is a legal dimension, however. Musical instruments have generally been considered exempt from copyright. The music created through the use of instruments of course is subject to copyright law. The instruments themselves are not.

Calling the Hang an “instrument for self-discovery,” or a “sound sculpture,” helps pave the way for copyright law to become applicable, if you can find a judge willing to go along with your reasoning.

In most countries, copyright law is long-lived and broad. If the Hang were to be recognized as a form of sculpture, instead of a musical instrument, that would spell the end of the handpan instruments, ie the instruments NOT made by PANArt.

Thanks for raising the question, it’s an important point for the story.