This does not reduce the overall cost, it just shifts it to the clearinghouse. Who pays the clearinghouse so that they can cover their own exorbitant SMS costs?
>>explai+c6
The clearinghouse may not have the user’s most recent email address, which is common amongst non-tech people. My mom and aunts have lost many email addresses this way and forcing them to use an older email would cause many issues.
>>supriy+i7
The app has to ask for email/phone to begin with (see step 1), if the email doesn't match then phone would be used as fallback, or potentially as a "Didn't Receive Code?" gesture.