The private servers I'm in always have a few people screen sharing whenever a voice chat is active. They're either sharing their gameplay (semi-privately, hence no Twitch) or they're co-watching movies. Oh and every so often, screen sharing is used for getting someone's opinion on image editing or a song in they're making. I've also given people remote tech support which is way easier to do when their screen is visible.

But it's worth noting that as an older Gen Z, this is just how people hang out nowadays, so we'll be watching anime together in the server until we fall asleep or whatever. That's why screen sharing isn't as useful as screenshots and video clips.