It would just be a good option to have my app not be destroyed and recreated on something as simple as a screen rotation. It would be nice to just get an Event when it happens and resize my controls. Destroying works fine for those using the designer, but for those building interfaces by code this would be much easier. Not only is it easier to manage the code, but the interface is much faster when just sizing the controls instead of them being destroyed and recreated all the time. I would much rather have my app only destroyed by the OS.
It would work best to have it just like one of the Activity Events or something. If they don't use it then nothing is changed and I'd guess internally B4A would just pass the event on and the App would get destroyed as usual. Otherwise the developer can process it and pass true back to avoid the app being destroyed. That may not be the correct way it happens and/or it may need reverse logic like if passing it on does nothing then B4A may need to call something that destroys the app and calls Create/Resume again, but whatever needs done to get it shouldn't be that much.
Some of the threads seem to also use it to capture keyboard events to prevent hardware keyboards from crashing the app when they fly out. The threads are a little old and I'd think that would be something big, so either it was fixed already and some code is there that could be easily tweaked to add this or this could be used to fix it too if not.