ebook readers yes. But they can work quite well on full-size tablets.
Kindles etc. are great when you're mostly reading a flow of text. For anything that benefits from design layout -- positioned graphics, sidebars, footnotes, etc. PDF on a 10" tablet is often better.
Ideally you'd provide a PDF as the most convenient format, but have a latex or similar root file that could be processed into other formats, like maybe .mobi or .epub.
