We really don’t like our learners seeing the WordPress admin bar. It’s confusing and it exposes the WordPress dashboard to regular users (there are much better ways for users to manage their profiles).
Enabling this module lets you turn off the black admin bar at the tops of pages for any roles that you want. Check off any roles that you don’t want seeing the admin bar and they won’t see it. For typical LearnDash sites, this will include the Subscriber and Customer roles.