In the core it´s really just showing users of a usergroup in the module.
The whole think looks like this:
I have a membership-site (payplans) and want to show all users that subscribed to the membership on the salespage for social proof. All members are in a special usergroup and they all have applied a ES-Batch as soon as the signed up for the membership.
So I need to somehow limit the users-module to show only users with the badge OR users of one usergroup.
In fact, the usergroup would be a little bit more usefull because it would be more flexible. However, I can work with bouth of it.
Important: I also use the module on other parts of my page with normal content (online-users), so this filter should not apply to all modules of that kind, only to one of them.
All the best, Julian!