One reason would be ApplePay. At least in Europe most payment terminals have their NFC sensors on their side, so you're supposed to hold your phone flat with th

One reason would be ApplePay. At least in Europe most payment terminals have their NFC sensors on their side, so you're supposed to hold your phone flat with the side of a box, so the selfie camera just points to the wall on your left. In that position, there is no way that the camera of your iPhone could see your face. Compare this to Touch ID, where you hold your phone to that box with your finger on the sensor and half a second later you've paid - very convenient. I would take a guess that Apple has not yet tested any iPhone X with a European payment terminals and will get a lot of angry emails once people try that combination.