I have a few extinction meters that were given to me over the years and I'm surprised just how easy and accurate they be. Even with no practice you can come within 1 stop of a modern meter and once you dial in the eye to the extinction meter over a short time I can get the same result. I do not use them but they make interesting discussion pieces and are rapidly being forgotten, I think. I also have a Curta sitting on a shelf in its plastic container. An interesting calculator designed by an inmate in a NAZI concentration camp.
That mechanical meter seems to have spawned the exposure chart on the earlier Roleiflex. A simplified version that takes into account the time of year, something modern meters do not.