On an anecdotal track, Robert Grant, in "Bush Flying: The Romance of the North" relates a story about celestial navigation saving his hide. He was getting some inflight celestial navigation practice, and his reading contradicted some piece of cockpit nav gear (IIRC, it was an ADF that the pilot was relying on). As it turned out, the ADF was malfunctioning and the aircraft was very off course, and headed out over the ocean.

IMO, Celestial Navigation is like reading Morse code or Semaphores. You may not ever have to use it, but when you need it, you really need it. It is also a relatively fail proof answer to the universal "Where the **** am I!?!" question that seems to indicate needing a rescue.