Basically, it protects email services like Office 365 or G-Suite as well as business communication like Slack and Teams, and offers advanced protection against phishing and attachments even before they reach the mailbox. It also includes a DLP (Data Loss Prevention) feature that can be configured to prevent sensitive information from leaving the organization via email. Additionally, it provides advanced security measures to protect against account takeover.
The email protection piece utilizes an API rather than an agent, which is more basic. This API-based approach allows for greater flexibility and integration with other systems. You can also configure it to send suspicious items to a sandbox environment for further analysis if you're not comfortable relying solely on the automated solution.