Face detection is one of the best features Google Photos has to offer. I personally use this feature to search for photographs of my friends and family. Until now Google Photos face detection worked automatically. However, this is set to change with the latest Google Photos update which allows you to manually tag people.
Google Photo’s face detection works very well, however some times it just misses out tagging pictures. With the manual tag feature, you can always go back and tag the missing person. There is one condition though, in order for you to tag the picture, Google should first detect that there is a face in the photo. If it fails to detect face you will still not be able to tag someone. The feature is yet to be available for everyone and it seems like it is a slow rollout.
Google assures that it doesn’t share details between accounts. If you use AI for face detection then Google will still not be able to detect the particular person inside a picture on another Google account.
On a related note, Google has renamed the Assistant tab to “For You.” As before the section will let you create new albums and order prints. Once you scroll down, Google Photos informs you that the suggestion for archiving receipts is moved to the “Manage your library” section. You can access the same by opening the navigation drawer by using the hamburger menu or with a swipe from the left. Google Photos version 4.32.1 is available for update