Nice article. I assume websites show some of the numbers not because users may have multiple phones but because users may change their number over time (and maybe they’ve not updated their phone number since opening the account 8 years ago). Labels (personal mobile) wouldn’t address this need, I don’t think. Although I suppose at that point you wouldn’t have access to the phone anyway so you’re probably not getting into the account!
Well researched.
Now its high time for websites to display a user-defined label to one of their many phone numbers and not to display any phone number.