Some accounts may allow users permission to edit features, but they do not want the user to be able to create new features. Further, they need the ability to restrict a user from assigning or editing the assigned release. A use case would be where releases are solely determined by a one-way mapping from a development system.
Users with contributor or owner permissions may create records or make changes that fall out of sync with the development system (if release is set only one-way from the development system)
Additional controls on a workspace role to restrict the ability to create a feature or edit a feature's release