SKU: AT-UHD-PRO3 matrices
Subject: What is the purpose of adding users if they all have “root” Access
You may see the below screen when logging into your AT-UHD-PRO3's web-GUI and clicking the Settings tab: 
Adding users is intended for audit support on installations that require secure telnet connections.
On some control systems, you can set up user audits where, anytime event such as a switch, function, or power cycle can be logged. By adding users and then turning on “telnet login mode” it will require a username and password for each command.
Article ID: KB01393