video has great value...
you know when I have left the room.
When my name is no longer on the conference roster, you know I have left the “room”.
Lack of video opens up wonderful opportunities to engage in a normal-sounding conference in exotic circumstances; so long as background sounds are neutral, nobody need be distracted by my discussing system designs, say, on a picnic table on a hill at the “Little House on the Prairie” homestead, in a parking lot at Mount Rushmore, or under a sun umbrella on my back patio. There are times video would render me unavailable (”sorry, have to take a vacation day”) due to distracting visuals when my involvement in an issue is necessary.