Why Microsoft Need send email from O365 not from SMTP gateway

Microsoft Office 365 (O365) provides its own email infrastructure, and there are several reasons why organizations may choose to send emails directly from O365 rather than through an external Simple Mail Transfer Protocol (SMTP) gateway. Here are some reasons:

Integration and Management: Microsoft O365 is a comprehensive suite that includes email services. Sending emails directly from O365 allows for better integration and centralized management of email communication within the O365 environment. It simplifies administration and reduces the need for additional third-party tools.

Security and Compliance: O365 has robust security features and compliance tools built into its email services. By sending emails directly from O365, organizations can leverage these built-in security measures, ensuring that emails are encrypted, protected against threats, and comply with industry regulations.

Authentication and SPF Records: Sending emails from O365 ensures that emails are authenticated properly. O365 manages Sender Policy Framework (SPF) records, which help prevent email spoofing and phishing. This enhances the trustworthiness of emails sent from the O365 platform.