Wild-Card Permissions give group members automatic access to each data source associated to a segment, destination, or trait. These wild-card permissions work only when your account is enabled for the RBAC (Role Based Access Controls). RBAC can be enabled from Audience Manager Admin Section for which you can contact Adobe Customer care (firstname.lastname@example.org)
Many users are in the "Read Only" User Group. But still they are able to create traits and segments. Why User Group permission is not working?