Many people have tried to describe Apple's Face ID technology instead of a more secure and easy-to-use Touch ID, and in most situations, that's the problem. However, some people have followed the Apple forum to tell the world that the face ID on the iPhone X can not be used to confirm and authenticate the purchase of the family on other devices.
Recently Apple introduced the Ask to Buy function to give parents control over the habit of spending their children. This feature allows other children or individuals within the limits of an adult, to request permission to make special purchases through the Apple ecosystem.
This is applied to prevent children from wrapping big bills when downloading apps or making in-app purchases. The idea that a request will be made, the adult device will accept the request and then the individual will approve or reject the purchase.
On earlier Apple devices, this authentication is possible using Touch ID but does not seem to be the case where iPhone X and Face ID are noticed. Instead of using Face ID to immediately approve the request, Ars Technica shows that parents or trustees now have to enter their own IDs and keywords to approve the request. It's not the biggest trouble in the world but it's a bit strange if Apple allows Touch ID to be used but does not include Face ID because of one thing and another.
It looks like Apple has not yet made an official statement on this issue, which means we do not know if this is a supervision to be fixed, or if Apple is concerned with the security of Face ID in this case. respect and therefore will not allow it to correct this type of request by using face detection.
The official support page on this subject indicates that the feature can be used to verify that the user is genuine but does not create a reference to Face ID. This is not the biggest problem in the world but it seems a bit odd given the importance of Apple wearing Face ID and its power.
(Source: Ars Technica)