Coach Brandon Hickman is the Head Coach and Offensive Line Coach at Jesuit College Preparatory School in Dallas. This presentation is on his Offensive Tempo Drill that they run daily.
The entire can be seen here.
Coach Hickman likes the drill because it prepares the line to play fast. He likes to change up the tempo throughout the game to keep the opponent's defensive coordinator off balance. Tempo is especially effective to run against defenses that move around a lot.
He likes to run the tempo drill at the beginning of practice to kick start the practice.
Anytime they practice tempo, the players run to the official and hand him the ball (rather than setting it on the ground after the play is blown dead) to be able to play faster.
Some of the times they look to tempo are right after big plays and when the defense is substituting. If the coach up top sees the defense substituting, his call is sub and they immediately go tempo.
Jesuit uses their whole offense when running tempo, but uses only two formations--10 and 20 personnel.
Running tempo in a game forces the opponent to simplify and play their base defense.