I encountered this recently, though I did not have a connecting flight to test out the features.

If anyone is wondering - it is possible to log in or out in the middle of the flight. By default, logging in would get your first name prominently displayed on the IFE homepage throughout the flight (it cycles between splash screens of your name and the flight's destination), though that can be disabled in the privacy settings.

I must say it feels a bit of a novelty to be welcomed by your name on the IFE, like in the early days of hotels welcoming guests on the in-room TV.