This setting displays the "Your IT department wants you to protect your important folders" window that prompts users to move their Documents, Pictures, and Desktop folders to OneDrive. This feature is not enabled for on-premises SharePoint.
If you enable this setting and provide your tenant ID, users who are syncing their OneDrive will see the "Your IT department wants you to protect your important folders" window when they're signed in. If they close the window, a reminder notification will appear in the activity center until they move all three known folders. If a user has already redirected their known folders to a different OneDrive account, they will be prompted to direct the folders to the account for your organization (leaving existing files behind).
If you disable or do not configure this setting, the "Your IT department wants you to protect your important folders" window won't appear automatically.