Earlier, wrote:

... Whether it is habit we can not accept digital meters.
For example quartz crystal watch, we almost accept it now...

Human factors studies dating back half a century show that our visual
sensory systems are most finely attuned to perception of angular
displacement and angular rate.

That is one of the things that makes it possible for most amateurs to
make straight wings; for folks with normal eyesight, sighting across
the top edges of two airfoil templates will easily get you below
1/4-degree of twist, and for most airplanes that's about as close as it
matters.

When it comes to input devices, analog meters are superior to digital
readouts in most of the aspects that matter for aviation instruments.
We are naturally very good at perceiving angular displacement and
angular rate at a glance.

We are also very good at applying "native calculus" to angular
information. One of the things we do almost without noticing is observe
the angular position, angular rate, and even angular acceleration of a
needle such as on the airspeed indicator, and integrate all of that
stuff to effect a smooth leveling-off from a climb.

It has been said that most folks prefer analog watches because they
don't really care what time it is, all they want to know is how long
it's going to be until their next temporal milestone. And the fastest
way to get that information is to observe that you have a 90-degree
minute sweep until your next appointment, and quickly filter that with
your learned understanding of how much you can get done within the 15
minutes represented by those 90 degrees.

All of that facility with angular input comes from our heritage as both
predator and prey. Those of our ancestors who could throw a rock and
bring down game, those who could detect a dangerous carnivore hidden
within a clump of swaying grass, they survived and prospered. That goes
back to my conviction that, if there is intelligent design, then
natural selection is in fact the set of rules that makes it happen.

Anyhow, when you look at your digital watch, you have to execute a
whole bunch of arithmetic gymnastics that you are programmed to learn,
but which are much less tightly wired into your brain. Suddenly you
find yourself subracting 8:45 from 9:00 in minute notation, achieving
the result of :15, and then interpolating that with your learned
understanding of how much you can get done in 15 minutes. It's not that
much harder than with the analog device, but it _is_ enough harder that
when split seconds count you can notice the difference.

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com/hp-24