"the Sentry Eye Tracker allows you to understand the decision-making process of professional gamers and improve your own gameplay by analyzing eye movement during competition..."
See where a person looks on the screen only tells you where they looked. It doesn't tell you what they were thinking or why they behaved in a particular manner. It's only part of a picture. Maybe if the user knew they were being recorded, asked to think allowed and then a follow up interview was conducted. That would give more accurate analysis of of that player's gameplay, motivations and behaviors.