Man. Sometimes English is an imprecise language. I guess the second quote I posted doesn't preclude scanning all photos. It would be a weird use of wording, but if all photos were scanned all the time, then technically that sentence would still be correct.

I'm not 100% sure if this is about the on-device portion of this. Gmail and OneDrive already use this (and have for the better part of a decade) and I haven't seen any large outcry. Also, Apple has confirmed that turning off icloud photos means this doesn't work (this is separate from iCloud backups).