Not necessarily. While processing fees are generally lower, there are additional fees associated with having an ACH account, and it is more cumbersome from an accounting perspective.
Also, ACH/Direct Debit/PAP is not processed in real time. This means that you will not know if your customer actually has available funds, or if you have entered the banking information correctly, for at least five business days. When you run a credit card transaction, you know immediately if the card has sufficient credit remaining and that the information has been entered correctly.