Not a fan of the deadlift video. There is no other way to move a deadlift then vertically along your center of gravity. The center of gravity is the middle of your foot. His method makes you move the bar horizontally.
if you move the bar back, it causes your shins to straighten up and in turn you to drop your hips way lower, often making the lift harder for people. If you look he pulls backwards slightly which would make it easier to incorperate the glutes and hips into the lift making for a stronger lockout too.