Hello,
this setting defines if the keys of the users that are member of a group with this Consumer Policy will have the "Email" product usage enabled or disable on their keys.
E.g. if this checkbox is activated, then all keys of users will have email as part of the product usage flags on their keys if it's disabled, PGP Desktop and PGP Gateway Email will deny encrypting emails to these keys, since the key is not set for usage with email encryption