I don't password protect the media files on the nfs server - they are visible password-free from any machine on my local network. Of course if someone has sensitive material and/or the local network is shared, say, then some extra setup is needed.

EDIT: another common use-case for me is basically grabbing lots of youtube videos/playlists via youtube-dl, which then lets me watch them on anything and everything than can run kodi commercial-free without jumping through hoops (i.e. browser addons or sideloading third party youtube apps, etc)