I've done these types of moves with Mindy Mylrea workouts and Tracie Long workouts. I find that, as others have said, you can go deeper into lunges, but also that when you slide into and out of a lunge, the non-moving leg works more than when you step into a lunge, and works more throughout the entire ROM of the move : all the way down and all the way up, rather than mostly on the push-off.
I'd say the move becomes more like a one-legged squat than a regular lunge.