This setting allows users to create and use secondary profiles, and use guest mode in the Lacros browser.
Similar to both BrowserAddPersonEnabled and BrowserGuestModeEnabled, if this policy is set to false or unset, the user cannot create or use secondary profiles, and use guest mode. Previously created secondary profiles, if any, will be unavailable.
If this policy is set to true, the user can create and use secondary profiles, and use guest mode.
Note, that if this policy is set to true but BrowserAddPersonEnabled is set to false, the user cannot create secondary profiles. The same for BrowserGuestModeEnabled and guest mode.