As reported by ArsTechnica, iPhone X owners are unable to use Face ID as an authentication method for the “Ask to Buy” feature, which lets parents approve their kids’ iOS purchases and downloads, even though the functionality was available on Touch ID devices. Instead, family purchases now require parents to enter their entire Apple account password to approve.
Although Apple allows Face ID as an authentication method for all purchases that previously worked with Touch ID, the method does not seem to work for “Ask to Buy” or Family Purchases for a reason not yet known to anyone. Even third-party apps using Touch ID now automatically use Face ID instead, making it even more surprising that it doesn’t work for an iOS feature offered by Apple itself.
Users are sharing complaints about this on support forums, but Apple has not made it clear why this limitation is in place. Apple has said that Face ID is most likely to be fooled by a close family member who bears a strong physical resemblance to the face data stored on the device. As a result, the users who have taken to support forums to complain have asked if Apple disabled this feature for Face ID because of the possibility of the child getting past it.
It is worthing pointing out that even if children could somehow get past their parent’s Face ID authentication, they could still simply make the purchase on the parent’s device and then access it on their own device via Family Sharing.
Apple is yet to issue an official statement regarding the issue.