Cable pullovers allow for a great stretch and full contraction of the lats. The added benefit of having your entire back supported by lying on the ground lets you focus on volume without the fatigue accrued by supporting yourself.
Remember, big lifts first, then do this low-stress finisher for added volume.
Thibs is on a mission. The angry Canadian wants to see the incidence of training stupidity decrease. Are you a "kitchen sink" trainer or coach? Have you misinterpreted the concept of overtraining? If so, duck!