"The myth I like to dispel is that Reading and improvisation are somehow mutually exclusive."
Yes. I would like to dispel that myth - if there is one - too. It is patently not the case.
Learning to play by ear before learning to read is benign. Leaning to read before learning to play by ear is not - and can be a major inhibitor of thinks like improv. It may only be a small minority who suffer (we don't have stats, I don't think), but the precautionary principle demands that we routinely teach beginners to listen and copy first, THEN show them the convenience of writing it down.
Big clue: You don't need a book to listen to music.