PushKit notifications also have the following advantages over user notifications:
- The device wakes only when it receives a PushKit notification, which can improve battery life.
- Upon receiving a PushKit notification, the system automatically launches your app if it isn't running. By contrast, user notifications aren't guaranteed to launch your app.
- The system gives your app execution time (potentially in the background) to process PushKit notifications.
- PushKit notifications can include more data than user notifications.
Sounds like PushKit notifications are treated like a full app launch, which gives your code access to APIs which regular push notifications don't give you (trivial example being location) https://developer.apple.com/documentation/pushkit?language=o...
But also some authors uses PushKit to keep their app constantly running in background.
I looked into that, the second answer here gives better but slightly dated insight on the matter, it makes sense: https://security.stackexchange.com/questions/119624/how-is-w...