If the custom fields are included the person who registered would know they entered their information correctly. Also the Notification email would go to staff who would be able to update registrations in the event the database person is not able to process in Raiser's Edge at the time the information is needed. An event with a limited timeline or a small maximum amount of registrants needs to be looked at frequently especially if multiple departments are involved in the event.
customized attributes are very important and see a need for them to be added to an acknowledgement email too. We currently have an engraved brick project and have found a gap in being able to provide a comprehensive acknowledgement email showing those brick inscriptions to the donor. Since it is a sizeable personalized contribution, it would provide a great benefit to the donor and to our institution.