Media Permissions gives you one more layer of restriction which WordPress doesn’t support by default. In WordPress media permissions checks against post capabilities. To delete a media they will need delete_posts capability. delete_posts capability allow them to delete their own posts as well as media. This check happens within the WordPress core. If you want a setting where you want the user to delete the posts but not the media, that’s when WPFront Media Permissions help you. So try giving the role delete_posts capability.