I was already logged in to FB and android/chrome remembered it. I didn't have to type password. Yes, its the real messenger app. I was wondering what is the poi

I was already logged in to FB and android/chrome remembered it. I didn't have to type password. Yes, its the real messenger app. I was wondering what is the point of sending review account email in this i.e.after sending the mail about a message and when the user chosen to interact and follow that email to message flow. Maybe its not much.