[aerohead]

Humans don't appear to have the facility to process audio information, as a sole means of communication.
Even Bucky Fuller refused to broach a topic, unless he had detailed illustrations or models, to help convey the concept.
For the uninitiated, any person accessible online, who can speak for 20-plus minutes, may get an automatic 'pass', as the viewer may make the presumption that, the ability to stay on target for that length of time somehow implies a command of the topic. A potentially fatal presumption, at a time when we can least afford such things.
Don't wake me!