I believe that even if the user enabled the capability, under the OOTB configuration, this change probably doesn't provide any additional security as root on sys-whonix can bypass onion routing.
However, I believe some users tunnel TOR via VPNs and if there were perhaps an attack on the tor networking or other components in sys-whonix, AND the user turned on the capability, a default value of (none) or whonix-ws might be safer.
B