So it's a lifting aid? Better mention it on the PB chart.
FF, looking up is actually worse biomechanically (although not worse than looking down so far that your upper back bends). It's something that's only recently started filtering through strength and conditioning channels, but most of the top coaches are advocating a neutral spine which includes packing the neck and tucking the chin. This basically means you initiate the deadlift looking at the floor, but the idea is to keep your spine aligned and not fix your eyes on a static point.
People tend to look up to reclaim stability in their spine due to having poor thoracic mobility or weak erectors and mid/upper back stabilisers.
Edit: it's also just a fact of modern life that most people spend most of their day with their chin too far forward so aren't aware of what a neutral spine all the way up even feels like. Try it in the mirror (or series of mirrors...), it will probably feel really weird.