Quoted from MikeS:
If you play with your phone you basically lose the ability to nudge which is a major component to playing pinball. That's why I can't see it being anything more than a gimmick.
They could compensate for this by giving you a higher score if you use the phone, or perhaps some other incentive. Kind of like DM where you earn a higher bonus if you play with the handles instead of the normal flipper buttons.