There’s an official Xbox integration in HA:
Xbox - Home Assistant (home-assistant.io)
We can do amazing things with it like turning on/of our xbox, do media player stuff and even be able to remote control our xbox (using HA as controller).
I couldn’t find anyone else requesting the same and the reason why this isnt integrated is prolly due to Microsoft Restrictions. But shouldn’t it be great to be able to monitor you controller’s battery level?
Personal use case: from time to time I lay under heavy fire, teammates are depending on me and my controller’s batteries went dead. Of course I can’t expect home assistant to replace the batteries in time for me, but at least my living room lights can be turned red and my GF can be send a message in a request to bring me some batteries (yes, indeed I want to automate my GF too 
).
There are surely more usefull values to be read by HA (like which game is started etc.) but for now this request is to make the HA Xbox integration being able to read out the controller’s battery level.