Same here - I tend toward military sci-fi (most of it is very bad) and so disposability is key to not building up a huge collection of junk. The few physical books I own now are tabletop RPG manuals, because they are needed as reference during games when batteries running down would be inconvenient.
Certain reference manuals (The O'Reilly Zoo, for example) are more useful as physical books, as well.
Besides, if I got hit by a bus tomorrow (not planning on it today), it's not there's anyone to inherit my stuff.
