So you are saying there is another Google API which provides the same functionality? I don't understand. If there is, why isn't this article simply suggesting people use that?
(Otherwise, I feel like you are just muddying up the discussion by trying to focus on the branding of specific APIs on different platforms rather than on what functionality is being offered, as if it matters what the APIs are called. Again: if I want to run an app--as many people do--which can incrementally slurp up all of my photos from Google Photos to store elsewhere, I should get to do so, the same way Google writes an app that slurps up all photos in my iOS photos library. If Google wants to shut down access to photos stored in their system without at least acknowledging the hypocrisy, that's pretty awful of them.)
