No idea on the HDMI, but when one considers the work put into the AES/EBU, coax and usb, with regard to taming sources of jitter and whatnot, on those three formats..
..and that HDMI is a complex system, more complex than the others and exists purely at the consumer level....
...and has had no jitter and noise taming for audio, in the high end direction...that no devices, chips or schemes to tame high end audio problems in HDMI exist...well..it clearly marks HDMI as the inferior audio data transfer format. all for a plethora of issues and potential issues, that are not easily detailed in simple posts on forums.