Having incomplete information in your database is equal to having no information. When most of your records have email addresses without any additional details, it may lead you to a great loss. Without any contact/business name, phone number, location, zip code or mailing address it is generally a tough task for you to reach to your customers.
The reverse email append will allow you to fill the gaps in your database and this will open newer channels to reach more customers. You can thereafter gain a better understanding of the needs of your customer once you get in touch with them and have all their details.