Why in User doctype , Phone has not option set as "Phone"?

I am replicating my question raised here: https://github.com/frappe/frappe/issues/6713

I was given a task of formatting Phone in an international format system.
Searching about it, there is validation in “Data field” if option Phone is set

But as I see in core doctype like User https://github.com/frappe/frappe/blob/develop/frappe/core/doctype/user/user.json#L702
this option is not set.

If where any reason that I am missing ?

Upgrading and adding more sophisticated Phone parsing libs like https://github.com/googlei18n/libphonenumber or https://www.npmjs.com/package/libphonenumber-js can be valid solution to upgrade this parsing ?