MemberPress User Roles GPL Overview:
User Roles integration allows site owners to set specific WordPress user roles on a per-membership basis. Meaning you can assign different roles to your members based on their Subscription status to your various memberships. These roles are added in addition to the default role you have set up in your WordPress -> Settings -> General page. It does not replace the default role, or any other roles that may be added by other plugins like bbPress or WooCommerce.
This will automatically add to or remove from the the user’s existing roles appropriately depending on their subscription status to your memberships. If the user has no memberships active, then their role will default back to the role(s) set in your your WordPress settings as mentioned above.