Listening intently to your computer, showing genuine interest in the work you are auditing while making notes.
Looking at your auditee directly cannot be replicated by your computer’s camera, yet.
Not to mention the sounds and smells of anything else that may influence your search for evidence of effectiveness.
And not to mention the pressure on your decision to agree evidence of nonconformity face to face with your computer.
I’ve not experienced any virtual system that does this, yet.