Exclusion Groups - Uses / Best Practices

Exclusion Groups are used for adding or removing users/groups from an existing security group. If you assign a security group to more than one securable role or page, you might need Exclusion Groups. If you assign a security group to only one securable item (ie all the Environment and System Roles and Pages have their own distinct group), there is no need for Exclusion Groups (at least for Application/System access). Initially I thought that Exclusion Groups were a really useful method for 'security exceptions'. With the 'single group assignment' method, Exclusion Groups are not needed.