Login option there as far as I know is to access ur router USING RADIUS or NOT. Its not for remove login to a hotspot or pppoe server.
U can check https://help.mikrotik.com/docs/display/ROS/RADIUS
"login - router's local user authentication"...
If u want to remove login to ur hotspot user, if it's just free for all, why bother using hotspot as ur way to spread ur connection? U can simply using DHCP methode or stactic lease DHCP for that user.
If u want to remove login to ur pppoe user, if it's just free for all, why bother using RADIUS, just use local user at pppoe server secret setting, then set always on dial from pppoe client router.