First, it teaches perfect form tackling. To drive a runner backwards, a tackler must bring his hips with his head up. Second, it allows the defense to swarm to the ball and work on stripping it. A running back lying on the grounds does not help our defense create turnovers. It also rewards the defender for pursuing to the ball.
Linebackers play football downhill and tackling is done on the go.
Often times the linebacker has been walled off or sealed. To prevent that from happening, our tackle drills include the LB defeating a clock on his way to the ball. The difference between a D-lineman and an LB is the distance from level one to level two. Our LB's are taught to take a hard route to the ball carrier. Oftentimes that means blowing up the outside shoulder of the blocker.