According to Alexandra Horowitz
The e-book hasn’t killed the book; instead, it’s killing the “page.” Today’s e-readers scroll text continuously, eliminating the single preformed page, along with any text defined by being on its bottom. A spokesman for the Kindle assured me that it is at the discretion of the publisher how to treat footnotes. Most are demoted to hyperlinked endnotes or, worst of all, unlinked endnotes that require scrolling through the e-reader to access. Few of these will be read, to be sure.