> Apple's proposed system did scanning on your device, whereas google's system does scanning in the cloud. That is the distinction.

No, the distinction is that Apple's proposed system only scanned photos you uploaded to publicly accessible iCloud albums and did so in a way that not even they had access to the results until you crossed the "99 images that match known kiddie porn" threshold. Even then, they had an actual human being review the situation to make sure there weren't 99 false positives on a single account before calling the police.

There was absolutely no possibility of calling the police for a single false positive, which is what Google is already doing today.