The user-login command is a useful tool that allows some advanced use cases. For instance, you can append a path after the username and be launched to that path. You can pass a UID or email instead of a username in order to log in as a user.

You can use the user-login to secure your admin user account. In Drupal, the user with the identifier of 1 is treated as the root and can bypass all permissions. Many times, this is the default maintenance account used to work on the Drupal site. Instead of logging in manually, you can set the account to a very robust passphrase and use the user-login command when you need to access your site. With this, the only users who should be able to log in as the administrator account are those with access to run the Drush commands on the website.