This trigger is designed to cover scripting scenarios such as running the script right when the app is opened. For now, there are only two events. We'll see whether some other events such as AppFocused could be useful.
In combination with other packing- and scripting-related features, I am targeting to streamline mini-app creation and make it possible to not bootup main EyeAuras UI at all. This is one of the steps.
Detailed information is available here