It certainly is. I can keep thousands of books on Kindle and read any at any time but there is something very enjoyable about reading a deadtree book that is just missing from the Kindle experience.
Part of it is that manually flipping through pages gives me a better mental model of the location of the information and thus its relatedness. For (good) textbooks I still prefer a hard copy to a pdf and I have a huge e reader so it’s not even about the formatting of the display.