What happened? Google Photos on the iPhone backs up all your photos by default, and, like Microsoft, Google "shares storage" between email and photos. The minute Google Photos was installed, it started backing up photos until the paltry free tier was reached, at which point it disabled the associated gmail account since it was "out of storage".
Talk about an anti-pattern; I spent a good chunk of time on that trip helping people get their storage back so they could send email again.
I'll never recommend Google Photos to anyone ever again.