It’s really easy to exhaust the free photo storage and then pay an iCloud storage fee for the rest of time so I see a clear way in which the camera brings in revenue.
Not if you get a phone with enough local storage for your photos and then download them to your computer. The 5 GB of free cloud storage are a joke anyway.
If you ever actually connect your phone to your PC for syncing files between the two you are an outlier power user and not representative of the average user at all.