The chant keeps the conscious mind occupied while you take in the text with your peripheral awareness. It also helps to maintain your attention on your purpose.
Can you PhotoRead and not take in the information in the book? Yep. Letting the mind wander off while PhotoReading is a way missing it. If you always do what you've always done you'll always get what you always got.
That's why the chant is important. It carries your intent. Letting your mind wander off and daydream is the same as allowing negative thought like am I doing this right . I'm not sure I'm getting. Always bring your mind back to your chant. It carries your real intent.
Alex