That's a good example, but I've seen a good few people streaming (usually people who aren't primarily known as streamers and have dipped in their toe during the pandemic) and now and again start doing something on their computer without changing scene from the full screen webcam. A public voting system to change scene could allow a person's audience to choose the right scene.

Obviously needs guards to make certain scenes ineligible for voting (e.g., anything showing the full desktop) so people can't attempt to see anything sensitive, but allowing certain scenes (e.g., those capturing games) could be quite useful.

Basically what @mrkwse said.

Another use case would be for esports, where spectators could potentially vote which team they want to spectate each round.

In SimRacing it could be used to select Cockpit camera, Track Camera, ...