I think because it’s the more secure setting.
It seems you just missed to enable the file server. There’s a info message that it will be configured with the VPN IP:
If you enable the file server, you can choose the IP:
To force an IP change for the instance samba1:
See also NethServer 7 migration — NS8 documentation
api-cli run module/samba1/set-ipaddress --data '{"ipaddress":"192.168.1.123"}'
If you set the samba IP to the host IP address, the fileserver link is shown and the samba icon should be visible again after a browser refresh.
To hide the file server just set the samba IP back to the wireguard VPN IP.