That option would start the command once, when the profile is loaded. You need to configure the command to perform the check periodically (E.G. using the "Repeating" option, or a loop action).
Do note that the command will be stopped, as any other commands would, if you stop all commands (E.G. using the button on the main window, a "Stop All Commands Hotkey" hotkey, the "Make VoiceAttack Stop Processing All Commands" action in a command, etc...).