It depends what you're trying to accomplish, which by the way Spencer was running those reps wasn't very clear. If you want to work on acceleration and top end speed, then running all-out for 30-60 meters is optimal. A hard 8x100m workout would be done closer to average 400 pace to with shorter rest to work anaerobic endurance. One is a speed workout, the other is speed endurance.
Spencer tried to do both at the same time, which increases risk of injury and might take away fitness benefits. Spencer ran well and got away with it this time, but doing workouts like that often over a long period of time could lead to an injury.