CelNav is the equivalent of throwing a log tied to a knotted line off the stern to measure your speed, (You never know when the Doppler might break!) or lead lines (never know when the Fathometer might break!), or Morse over flashing light (the radio might break!), or sails (the engines might break!), or timber raft building (the ship could sink!).
I enjoy CelNav. I enjoy baffling the kids with stuff they don’t learn in school (lunars, double altitudes, deriving longitude by moonrise without a clock). I also know these skills are oddities of a bygone time that are as likely to help me as an astrolabe.