[notacoward]

Yes, they're useful, but I challenge the claim that they're essential. People have been communicating effectively over both time and distance for centuries, using media where these cues are absent. They're nice to have, they can make things easier and improve comfort/trust levels, but whether you rely on them is up to you. Lots of people at all levels of language competency and introversion etc. manage to collaborate just fine, even without any form of video at all.