Apple's photo search has been an outstanding application of on-device machine learning models for almost a decade at this point.

FaceID has proven pretty popular tools.

Good point re:photo search - I should have been more specific about what class of AI tool I was referring to. Photos seems like Apple's traditional approach of focusing on the user experience, whereas a lot of the “Apple Intelligence” features really seemed like they were shipped on the schedule demanded by Wall Street analysts rather than something the Apple product teams must have been happy with.