If I have to explain one more time when I'm trolling, ![Rant :rant:](https://www.eevblog.com/forum/Smileys/default/rant.gif.pagespeed.ce.koOB_HE-VX.gif)
![Laughing :-DD](https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif.pagespeed.ce._hfWAz_QHO.gif)
@Robert, the example with the meters you gave is a problem of observation and basic knowledge, rather than any inherent advantage in either technology.
The human eye is an intriguing piece of evolutionary technology; primitive in some aspects, yet astonishingly advanced in others.
In terms of discerning small changes, a good wobbly pointer will always exceed a DMM, for the simple reason that it effectively has infinite resolution*, whereas the DMM has to measure a defined quantum change before it indicates a change, ie for a 20,000 count DMM the magnitude of the reading must change by 0.01% just to flip the LSD, which may sound like a small amount, but compared to the magnitude of a movement the human eye can detect, it's hopelessly imprecise.
Also as you point out, the brain is evolved to use the information from the eyes in a certain way, which can make it faster reading analog output, though I'd argue training the brain is possible in such a way to make the difference negligible, in certain circumstances.
EDIT: * Assuming zero friction in the movement, and perfect linearity in the return spring. Obviously this isn't possible in practice, though I suspect the effective resolution on a good quality unit would still be enough to make a volt/time nut salivate.
Pointer wobble.
On PCC streetcars, the low voltage control power was made by a motor generator set that would use a 600V motor to spin a 32 volt ish generator on the same shaft along with two squirrel cage fans and in some cases a small belt driven air compressor. Anyhow, the original voltage and regulator was an electromechanical device that would series and shunt regulate the output side of the generator so that it would average somewhere around 34 volts or so to charge the batteries and a second electromechanical device called a reverse current relay would keep the MG set disconnected until it was spinning and had self-excited enough to produce more voltage output than the batteries. This allowed the self-excitation cycle at startup to happen without it being loaded down and also prevented backward power conversion by motoring the generator side of the MG set off the batteries on the car.
The pointer wobble would come into play on the voltmeter on the dashboard. The regulator would be switching in and out a series and a parallel resistance on the output side of the motor generator very rapidly to average the output voltage around what it had been set to across whatever range of loading conditions were present on the low voltage systems and the needle would be quivering as the generator ran and the voltage regulator acted on the output and all's good. If the generator side died or something went wrong with the regulator or reverse current relay, you'd still hear the machine being spun by the motor side but the meter needle wouldn't be quivering. It'd sit at whatever the voltage of the batteries was when you looked at it and you'd know you had a problem even before the batteries had a chance to drain off enough to seriously lower the pointer out of the range it should be sitting in.
Anyhow, after a lot of place including museums retrofitted these really fast acting solid state regulators in place of the original ones and put a diode in to replace the reverse current relay, the output of the generator would be flat on wherever it was set and the whole idea of looking over at the dashboard meter for pointer quiver as an at a glance check of the health of the motor generator and charging system went out the window. Oh well.