The feature is like a precursor to Augmented Reality. A user could take a photo and with one click get information about it. You could be in Chicago taking a photo of the tallest building and in one click you'll see 'Willis Tower' labeled on your photo.
Google Lens could go one step further by allowing a user to take a photo of a poster of an upcoming event and in one click they would be able to access Ticketmaster for tickets or more details of the upcoming event.