There are some things in the explainer about what a developer might want to do with an API, but it isn't clear what the underlying use cases are, so it isn't clear how these things matter.
The first use case I can come up with that actually explains to me why this might be useful is sign-language interpretation, where you have a limit of one PiP and there is a viable body of externally available content that could reasonably be found by a browser (perhaps via an extension), as well as signed tracks provided by the video website themselves.
Do you know of other examples that actually explain what people will do with this?
Somewhere in my mind is the ability to provide advertising - and to simply deny PiP as a way of blocking it, and using the main video as collateral to convince the user to just leave on PiP by not playing it unless the PiP access is granted. I can see this working for an advertising / video provider, but it doesn't seem like a great addition to the Web Platform.
What do people actually do with the Safari API?