The ability to read a book, a newspaper, whatever, at a congenial font size is part of what makes the Kindle such a pleasure to use. The demographics of older readers with aging eyes like my own make this a strong incentive to get involved with electronic (and configurable) text.
But what about students? Research that I have seen over the years suggests that font size also plays a part in students’ ability to access text. We certainly see larger text supplied for very young eyes in picture books and early readers. What we don’t know about how the size of print affects older students’ reading is astounding. That is another reason to investigate the Kindle for educational purposes.