NOTE: Objective-C battery information do not work in the (xcode) simulator. You will need to test this on a real iPhone or iPad. (This is not a Gamemaker Studio issue, its just how the simulator works).
There may be many reasons why you should check the battery status of an iPhone or iPad. You may not want a player to start a multiplayer game with only 5% battery left. Or, knowing if they are going to run our of power soon, maybe is a good idea to autosave or as the player of they want to save.
This extensions allows you to see the battery percentage left, and see if the phone is charing or not.