I understand this article is about face detection, but on a tangential note, face identification against known faces in the Photos app has been laughable for me on iOS 10 (haven’t checked if this has improved in iOS 11, since I don’t have many new photos with new faces). Even with some manual training, the face identification and name matching seemed quite primitive, getting most of its guesses wrong (for example, matching kids’ faces against adults’ faces).

That said, I do strongly admire and appreciate Apple’s stance on privacy and the software doing these kinds of work on the device and not on the cloud. I can wait for these things to improve.