It's happened to me a few times in lessons that my teacher would say "Wait, that's a bad way to do such and such, what you have to do is this..." and then she'd describe some movement. I'd try to do what she said, and she'd say "No, let me show you." Then I'd do what she showed me and she'd say "OK, you've got it."
But....then I'd say "well, the way I'd describe that movement is thus and so," and she'd say "No, no, no that's wrong, you have to do what I said." But I just did whatever it was according to the description I'd given myself in my head, and it worked fine. So I think verbal (or written) descriptions of technique and movements have their limitations, because
1. Not all teachers actually understand the anatomy and mechanics but use specific anatomical terms and get them wrong.
2. The teacher may be describing what it feels like to make a movement rather than what's actually happening (e.g. "keep your fingers completely passive, the sound comes through the arm" even though you can see perfectly well that the teacher's fingers are not, in fact, completely passive.
3. Particular descriptions of technique and movements get attached to particular schools of pedagogy and since there's a certain polemic between schools of pedagogy, teachers may become more attached to a particular description of movements than is really justified by the results.
Videos can be a bit better than books, because at least you can see what's happening, but I teacher who can give you feedback (even if their description of what you should be doing is unclear) and show you what to do is best.