Why is there braille on drive through ATM machines?

[davidm]

*Originally posted by XJETGIRLX *
…Because of the personal nature of an ATM transaction the person to whom the account belongs must be able to make transactions on their own, without the assistance of another person. This is to ensure the privacy of the transaction and the right to privacy of the disabled person. While they may need someone to chauffeur them to an ATM, they must (under law) be able to complete the transaction on their own, hence the braille…

But they still can’t complete the transaction on their own. How do they read the display? What good are braille buttons without some sort of braille, or audible, display?