LANs aren't air-gapped though and are insecure (yes I know stateful firewalls and good hygiene, still insecure). When that network is compromised you'll want a

LANs aren't air-gapped though and are insecure (yes I know stateful firewalls and good hygiene, still insecure). When that network is compromised you'll want a layer of authentication between an attacker and your filesystem.