Manually transferring iCloud Mail to Gmail involves setting up both accounts in an email client like Outlook or Apple Mail, and then dragging and dropping emails between them. This method can be tedious and error-prone, with risks like lost attachments or misplaced folders, especially when dealing with large amounts of data.

A more efficient option is to use the iCloud Backup Tool. This tool automates the entire process, allowing you to transfer your iCloud emails to Gmail without any manual setup or risk of data loss. It ensures a seamless migration while preserving the structure and integrity of your emails.