I read lots of research papers and books. I have tried to switch to e-readers several times, but it never works. I learn the subject slower and I remember much less of what I read from e-reader. I use computers and e-readers to skim or check some details, but never to thoroughly study.
If I read physical book or printed article and underline it, leave coffee stains on the paper etc. I'm working with actual physical object. When I achieve the paper in a map, I can often recall where the book is stored physically and even the coffee stains and notes in the paper.
I think physical book or paper works the same way as memory palace technique. You remember stuff by working with them physically better than in abstract. Physical library might be mirrored in our mind. Ancient augmented memory technology we did not know we have and might lose. E-reader or computer associates everything to the same object.