The need for an all-Privileged user

Although this mechanism allows you to avoid giving users the power to act as superuser, sometimes it is still necessary for a user to act as the all-powerful superuser, such as when diagnosing system problems, or cleaning up after a system crash. To support this, the current privilege mechanism still recognizes a process with a UID of 0 as possessing all of the defined discrete privileges. In effect, the root user is still superuser.