By complying with legal and technical standards that reflect market requirements, CSA senders benefit in a number of ways. In addition to improving the deliverability of your emails, the CSA provides tools to protect your reputation. For example, permanently retrievable data helps to identify potential issues that could damage the sender’s reputation. Certified senders also receive valuable feedback via dedicated alerts from CSA experts when non-compliant mailings are sent.
You can find a detailed description of the benefits here.