I’m hoping and assuming that apps would need to ask for permission to use this, lest this turn into every app fighting to push their own dynamic island notification to the top bar, just like how back then every app wanted to have its own persistent notification and also that time when every app provided minor status updates using global toasts that didn’t specify which app created it, so you could be doing something in a completely different app and you’d get a completely random and unattributed toast with some vague message like “connection failed” with no way outside of third party apps to figure out which app sent it. /rant
I used to have a lot of apps back then that would use them as advertisement banners, it was really annoying. I forget when it happened but I’ve been using Android since honeycomb so I’ve seen a lot