That's a fair point—if you move internationally, you can't keep your phone number. I'd argue that's a fairly niche edge case, however, which still leaves us in

That's a fair point—if you move internationally, you can't keep your phone number. I'd argue that's a fairly niche edge case, however, which still leaves us in a better situation than most digital identifiers. Google could relinquish my email address at any time for any reason and I'd have no recourse.