By using Microsoft's Outlook app, the synchronization process with Microsoft 365 is done securely and efficiently, as it is designed to work seamlessly with Microsoft's email, calendar, and contact services, and often aligns with corporate security policies that may include remote management features and encryption. A third-party mail app may not always adhere to the corporate security policies, as it could lack certain security features or data handling protocols. Enabling only IMAP would synchronize emails only and not calendar or contact data. Lastly, manual setup using Exchange protocols could work but isn't recommended over the Outlook app, as it is more complex and error-prone.