I took a course that had an e-textbook option. It was a big mistake. It was $10 less than the paper version, but you could not download to a device (you had to read it off a secure website and be logged in), could not cut and paste for posting on the course message board, you could not search because some of the chapters were just image scans that had not been OCRd, and the book 'expired' the day after the course ended. There were no usability benefits to having it in e-form (e.g. the search or the ability to cut and paste into the course message board since this was an on-line course) and in fact there were deficiencies since I had to be AT my computer to use it. And it expires to boot? For such a paltry price difference, I would have rather paid $10 more and gotten a paper copy I could keep. It was an epic fail.
That said, as a college English major, I could have saved a fortune had ebooks been available as they are now. I got a complete works of Shakespeare WITH scholarly articles and footnotes for $2.99 off Amazon. That same sort of book, in paper, was $85 back in 1997
And all those obscure Victorian poets we read for two classes and never looked at again? Available for free on-line these days...