The days that I frequently need logs are the days that I need to prove that a particular application did a particular thing -- handled a particular transaction, sent a particular message, responded to/triggered a particular event, and so forth. Faults in these areas are applications software faults (often not even fatal ones), and are unlikely to affect the logger process at all, especially since it is insulated from the applications softwares by each running under the aegis of its own dedicated unprivileged user account.

Crash diagnosis is but one use for logs.