Obviously people need to log in to see stats. That’s a somewhat private thing 😉
If you use the front-end dashboard you can use some kind of login widget/form on there as well so they can avoid the back-end. Or just let them in the back end, and you don’t have to set up a front-end page and stuff like that.
If the users are assigned proper roles they don’t have access to anything but their profile and AdRotate.