Computer-displayed text tends to be a lot smaller in practice (in arc-seconds on the eye.) A flyer's 96pt masthead might have be scanned from arm's length; a 20pt paperback page might be read rested against one's chest. Right now, though, I'm reading this page zoomed out on an iPhone 6, at the same visual distance as I would with a book—the text ending up at most 1/3rd the perceptual size it would on the book. The backlight-powered contrast makes it legible nevertheless, but I can't imagine how the text could be styled such that I'd notice, while retaining its legibility.