The old slide rule certainly is a bit historical, as is the whizz wheel version.
However, it does have the advantage of no batteries to go flat at an inconvenient time.
people get used to putting in the figures the wrong way round and get the wrong answer and don't go back to basics of 'roughing-it-out' first or sense checking things
That's the crux of the matter, though. Far too many kids and not so young adults who were brought up with calculators instead of times tables, have no idea of where the answer ought to lie in the scheme of things. If engineers etc., do it this way .. bridges fall down, etc. If pilots do it .. aeroplanes run out of gas, waypoints don't turn up, and so forth.
Bit like raw data and using the automatics .. best to be competent with both ..