After listening to the well-crafted English Suites midis from the Dave's JS
Bach Page, I changed my sceptical view on classical midis.  Here are the
two purposes of classical midis, to my opinion:

1.  To know the approximate sound of a composition that is very seldom
recorded, that you don't have in a CD and need to listen to right now or
that you don't want to spend money on for some reason.

2.  To show the maximum degree of voice separation and stability possible
in polyphony - yes, emotions are absent from midis but they let you imagine
a performer who could separate the voices ideally (I'm convinced that
Gould's favor to Walter Carlos' funny tracks was a secret envy to the
separation of voices that the computer achieved and that Gould, as a
perfectionist, would want to achieve himself).

Could you add your opinion on the purposes of classical midis to this list?
Thanks!

Juozas Rimas Jr (not the one playing)
http://artists.mp3s.com/artists/141/juozas_rimas.html