This read-write TruthValue controls whether successful login events are additionally written to a persistent login file on the device, separate from live syslog output. An admin cares because a stored login file survives reboots and syslog rotation, giving a durable local record of access even if the syslog server was unreachable at the time. For example, an admin without a centralized syslog collector would enable this so successful logins are still retrievable locally after the fact.