I still buy most of my science non-fiction books in hardcovers because
1.) they are more like reference books than a "semi-disposable" item like a novel
2.) they have charts, tables, and illustrations that do not work as well on a 5 or 6 inch greybeard screen
3.) With science books, if you are willing to wait, you will usually be able to get a used hardback in nearly pristine condition for a few dollars (or often for a penny plus shipping.) For example,
here is a book that I have in hardcover. A used hardback is 5 bucks. A Kindle copy is 40 bucks.