ZD, your mistake is the assumption you made that the question was asked about the Kindle Fire. You are correct that that particular model, as well as the Nook HD, use LCD screens like those of ordinary tablets.
However, the question was asked about the Nook Nuki, which uses e-ink, and Barnes and Nobles still sells Nooks with e-ink, and Amazon sells a Kindle with e-ink; I assume the shaila was about these as well.