I agree somewhat with both of you: Video does add a little to the technical complexity - but it is getting easier and easier. The main reason for not adding video seems to be that it means the presenter has to look presentable - that's not a good enough reason if it video helps to make a more engaging experience for the audience. On the other hand, I don't agree that 90% of what a person is communicating doesn't come through in a voice-only channel. Not sure where that figure comes from (possible a misinterpretation of Mehrabian's 1967 study?) but it's not credible. How do you account for the effectiveness of telephone communication over many decades if that were so? But I do think video of the speaker does add to the audience experience and helps keep people engaged. Not doing it just because we have to dress up is not good enough.