Generally, you'd have to have your bank account hacked to have a reason to reverse a charge on these types of systems. It happens, but very, very rarely and the banks have a lot of reasons to make sure it doesn't happen. That or you gave money to a scammer and that's your own fault (but they'll still help you).
This is why the fees are much, much lower. Often these systems even verify that you actually have the money and can transfer the amount to your business bank account on the same day. You can't do that with credit cards.
