>Intel is working on adding analog audio over some unused pins on USB 3.1.

This was some bad reporting by one of the tech blogs last week - Intel was talking this up at IDF in 2014 and the author of this article didn't fact check it (and admitted his mistake on the Reddit discussion of this article). Audio adapter mode has been part of the usb type-c connector spec since its conception. Passing analog audio out over a couple pins is part of the spec, and not in any way experimental or undefined.