As the post says, the React team isn't saying you _should_ do that. They're just trying to make it _possible_ to do so if you _need_ to.
One reason is that you can incrementally migrate parts of your app to React's upcoming Concurrent Mode if desired, while leaving the rest of an existing app in place.
One reason is that you can incrementally migrate parts of your app to React's upcoming Concurrent Mode if desired, while leaving the rest of an existing app in place.