Why would a ruler marked in binary not need to be as precise as a ruler marked in decimal? Changing the base of the numbers does little to affect how one attaches it to the wall.
After it was manufactured, it could be calibrated and the counter could then tell itself that 100cm is actually only 98cm due to manufacturing tolerance errors, for example. Then, after it was installed on the wall one centimeter too high, it could then be re-calibrated to reflect that error as well.
Abstracting the way the device counts (incremented binary marks on the wall) away from the measurement (inches or centimeters, etc) with a re-programmable digital device has many benefits.
