Yep, Taken hit it on the head. I like to to print manuals in 2 x 2 pages front and back (8 pages per sheet) of 8 1/2 by 11. (I have good eyes and have zero problems reading text at 1/4 size). Then I cram a LOT of material into a small space. But I also plan ahead and have plenty of charging ability between my hand crank and my 2 solar chargers to keep my phone going indefinitely as long as it survives.
With a little planning, both can go with you and keep you covered. Now in a situation where its an emergency, the odds are better my phone will be on my hip and not my survival manuals. In a bug out scenario, I would either have time to grab my tote of books and pack it when we go, or I'll go in a hurry with just my pack with just a couple books, but my phone will be on my hip either way.
No reason not to have both. But since I spend 99.999% of my time in a non life or death situation, having the extra abilities of the digital devices just makes a whole lot of sense. Considering if I am in a do or die situation and all I have is what I have on me at any given time, I'm willing to bet I'll have my phone and not my stash of printouts. But for day to day, sometimes it is nice to grab a booklet. Plus I can always throw one to someone who needs it and still have it on my phone. Win, Win.