All of the press implies that this lets you make payments by bumping phones. If you have actually used the application, you will see that all it does is send the person's email address to you.

Because Bump is not deterministic(ie, you could get a random person's contact info if you are say in an auditorium at SXSW), you still have to confirm that this is the contact you want. Overall, it probably takes more time than just typing the email in, and then you have to go through the normal payment flow anyway. There would be value if it transfered the entire vcard to your address book at the same time since this might be a lot of info.