The use case is anything that requires you to provide a number to receive a confirmation text. From registration to a personal data hungry website (facebook, go

The use case is anything that requires you to provide a number to receive a confirmation text. From registration to a personal data hungry website (facebook, google, etc.) to two factor authentication. At some point in the past collecting user email addresses became the standard and using disposable email addresses was the answer. More recently the trend seems to have upped to collecting phone numbers to which the answer is those public text services.