I would agree that there are benefits to excellent processing speed. DD9 would be an example. A teacher gave her a chapter book at the end of the day yesterday to read at home. She was finished with it within an hour of arriving home. FWIW, she had an excellent PSI on the WISC, too. I think her processing speed places her at a distinct advantage on timed tests. Also, when she is motivated, she digests material incredibly quickly. She is a very quick study.
While it is often thought to be the measured portion of intelligence testing that is "least" important, being a "quick thinker" definitely benefits DD.
Of course, her WMI isn't that great (although still comfortably above-average), giving her a definite "absent-minded professor" presentation.
I'm actually interested in the interplay between processing speed and working memory. DD never memorizes material, but she ABSORBS it, quickly and deeply. She clearly remembers what is interesting to her, and fortunately, much interests her. I do wonder how being a quick thinker impacts development of memory. I wonder whether DD relies on rote memory less often (and is a result, it is underdeveloped), because her store of knowledge is large due to her curiosity and ability to think quickly.
