Scott Reams wrote:
...understanding this does not suddenly allow a singer to sing every note
perfectly on every take. Pitches sometimes slip here and there, even if the
vocalist "understood" that they shouldn't have.

Sure. So what? That's called "performance." It's a human activity. Some
humans are better at it than others. Changing pitches that are humanly
incorrect to ones that are inhumanly "correct" doesn't make things
better. What makes things better is for the humans to learn more and
practice harder.

James Boyk