Pay-by-phone and carrier billing let you buy digital goods or services and...

https://delta-wiki.win/index.php/Mobile_Payments_Trend:_Why_Everything_Is_Moving_to_Wallets_and_Biometrics

Pay-by-phone and carrier billing let you buy digital goods or services and charge the cost directly to your monthly phone bill or prepaid credit. It’s a simple way to pay without needing a card or cash