twocats don't know if you saw my comment, but I think this applies to your Horowitz example.
Hmm, I guess what I'm saying is that there's a point of diminishing returns. All pianists must aim to have at least something like 98% accuracy. But after that point, high level musicality will have more impact and be more satisfying than getting it to 99.9%. And an audience would likely not care, imo, unless it was made up of score-clutching elitists tallying every last wrong note. (It would also matter for competitions, of course.) I do believe that there are fundamentally different levels of musicality, which are dependent on touch, control, and the like, and people pay more attention to those. It is why a great pianist sounds like a great pianist after 5 seconds of playing.