The sudo command and sudoers file are both very flexible. For example, you can configure a user to be able to execute exactly one command as root. You can also set up a group of users to share the same sudo abilities. For more information it is best to consult the online help using the following commands:
sudo (together with a fine grain sudoers configuration) is particularly useful for remote access and backup. For example, you can configure one user account (say, backupper) to have root access, but only to run a script called backup.pl. The script should only contain as much system access as necessary. In other words, even backupper is not root, it can still back up all the files in the system as root.
This way, even if the account backupper is compromised, a hacker can only perform back up operations as specified in the file backup.pl, instead of gaining full root access to all commands.
This method can be combined with the flexibility of ssh (using the Match and ForceCommand options of sshd_config) to limit a remote ssh session as backupper can only execute the command backup.pl and nothing else.