On the phone, "freeup device storage" is an option that is prompted (and sounds like a wonderful idea)... whereby the phone copy is purged if the original file has already been "backed up" to Google.

It isn't possible to restore the backup.

...And which gives you a modal warning box that starts "Heads up! This will delete n original photos and videos from your device". And will only proceed if you click an all-caps confirmation button labelled "DELETE".[0]

That's hardly comparable to Apple deleting things automatically, silently, with neither warning nor confirmation.

[0] http://www.androidpolice.com/wp-content/themes/ap2/ap_resize...

Even with the warning, people assume that backup means they aren't losing anything, and can get back the original pics whenever they like. In fact, image data is being lost here. You can never get back your original photos, only highly compressed smaller sized JPGs that will look OK on a mobile screen.

There is an option when you turn on Google photo to backup "High Quality" (Unlimited) or "Original" (with limited capacity, I think it uses Google Drive capacity but am not sure)

.. Unless you choose exactly that option when presented at install time. So people may regret getting exactly the behavior that they chose?

You can choose whether to backup converted photos or originals.

OK get you, I personally don't mind that sort of thing if I am explicitly asked but I see what you are saying.