Disagree,somewhat. The dots have 'some' place as far as watching a match but i don't think they help teaching/learning much. IMO most players learn how to use spin by watching the cb's reactions/movements and not looking at the ball spinning. Pool was played a gillion yrs before this thing came out, you really think players have improved because of it? How did Efren, Earl, Mosconi,Buddy, etcetcetc ever get so good without one?
On that rare occasion that I teach pool, I will often ask my student to announce their stroke choice in advance. The measles help me to determine whether they successfully executed that stroke. If I said to my student "you did not have any left english on that stroke" and they say they did, one of my go-to lines was "the measles do not lie." As the greats of the past have shown, you can become extremely proficient without the measles, but the measles have definitely made the instructor's job easier, and todays instructors are leaps and bounds above those of yesteryear. It can be, similarly, argued that those that developed a very high level of proficiency without the measle ball would have gotten there slightly faster with it, although we can never be sure.
It is regularly contended on this forum that improvements in technology, equipment and teaching/training aids are a big part of the explanation of why players today shoot so much straighter than their counterparts of the golden age of pool. To me, the measle ball fits right into that discussion.
To sum, yes, I do believe that the "spin feedback" offered by the measles has helped players to improve. Your suggestion that a top player may be able to sense/read the spin anyway based on other factors is logical, but do you really think that the developing amateur player can do the same? My experience says no, and to them the measle ball offers great value.
Not beers 
Well wait a minute. In my best performance in a 2 day event held twice a year at the white spot. Starting at noon on Sunday.. I had at my table a glass of water a bottle of beer And a cup of coffee. 
ever finished one. Just a sip available for my time meditation medication in the chair.