It has the appearance of working like this:

  1.  Epub of a book exists on a computer
  2.  User takes simple action to read that book on a Kindle device
  3.  ???
  4.  User succeeds at reading that same book

Like when Github invisibly renders Markdown into HTML for display in my browser: It seems rational to say that I'm reading a Markdown document.

Or when I print that same HTML onto paper and read it. I'm not reading the HTML nor the Postscript intermediates: I'm still reading a Markdown document.