For earnest reasons? 8bitdo does firmware updates to improve stability and latency, and fix features broken when Xbox, or Nintendo update something on their consoles. All using a stand alone app that just phones home and downloads the latest firmware payload for ALL its controllers without any login.
EDIT: You don’t even need the app. 8bitdo’s website has all their firmwares available to download and install as and when you need. The app is so dyslexic fools like me don’t accidentally brick something with the wrong payload.
Microsoft however, may push some bullshit does nothing update simply to make you sign into their app.
The purpose is allergies and a night’s sleep without coughing and sneezing. If you don’t have sinus problems before, you may develop them later in life from excessive exposure to dirt and dust.