You can take the the book/printed docs with you to read/study them at night, at work pauses, in the train, etc. Libraries don't usually let you take their computers with you, at least in my country.
Paper is an amazing medium for transmitting information: cheap, battery-free, easily copied or lended, transferable, DRM-free, non-proprietary, no monthly subscription needed...
The issues with batteries can be mostly, though not entirely, averted with e-readers, which use html (epub is just a zip with some xml metadata).
Now books, easily copied?
When's the last time you tried to share a copy of a book with a friend? Or did you buy a blank and copy it by hand? While that's a laudable example of dedication it's not exactly easy nor convenient.
Cheapness is likewise debatable, printing out a 300-pages book is fairly expensive.
Most other concerns are concerns only if you use broken-by-design sources.
