Registering your IP with Customs and Border Patrol (CBP) allows CBP agents to act as a gatekeeper, by allowing them to directly stop the import of infringing goods into the United States at the border.
After registration, CBP will check imported good for potential infringement of your IP and will seize those goods at the border, without any further action taken by you or your company. You have worked hard to ensure that your IP is proprietary to you, with registration you can let the CBP agents to do the enforcement work for you.