I've only had it when demanded by managers, who generally associate "work" with yakking in person because it's often the only thing they know how to do. I've never been requested by another dev to switch the cam on - what with talking, typing and screen-sharing, it's just an unnecessary thing to distract focus.

More expressive communication.

I was a bit of a sceptic initially, but now that I work in a company with a bunch of remotes (and am temporarily remote myself due to The Plague), it really helps.

I prefer text and voice over video, but for some situations video can be more time efficient. Several people can communicate aspects of their thoughts and opinions with facial expressiond (or head movements) simultaneous with one person talking, without interrupting.

Mostly it is a gimic, but my kids did have a class where the teacher asked them to raise their hands before speaking for which you need video. (there is a raise hand option in the call, but to explain how to use that to kids or teachers...)

Majority of my company is remote. Well, 100% of it is now, with the pandemic. That said, no one streams their face or watches anyone else talk in 1080p. 720p is fine.

Turn your lights down low. Sometimes it's like laying in bed next to each other... ;-D