In the name of the Pizza Lord. Charge!
Ereaders are great for reading novels and tablets are great for reading pdf's of books too heavily reliant on very-specific-formatting to look good on ereaders (that is, they're packed with charts, images, etc.). The only exception to that I've found is a few very large books I own, physically one is 12" x 15" for example, but I also have a pdf copy of that one and trying to read that on a tablet is a huge pain - constant zooming in and zooming out, scrolling around, etc., so I'd just as soon pull out the physical book instead. If I didn't get 99% of my books from the library where 99% of the books are physical, I'd have gone totally digital by now, so I guess that puts me in the "prefer digital" camp now.
I also have a lot of large art books, cookbooks and encyclopedias around 8x12 inches and above, and I wouldn't want to replace those with digital editions either.
E-ink ereaders were intended for novels, and I always get surprised at how many people want to read PDF files on 6 inch screen. I tried it and it's a horrible reading experience. Especially with PDFs that include pictures, charts or any graphics. Even when they are all text it's horrible. They weren't intended for pdfs at all and you shouldn't use them for that. You wouldn't use a fork to eat soup. But people will be people.