also make a power team look silly by using their speed effectively. If you look statistically teams that out run their opponents by say a 2 to 1 margin generally win the game even if the other team out passes the power team by a 2 to 1 margin. Running yards just enable a team to control the finite aspects of the game better because the game is played within a time frame. A strong running team also eventually makes their passing game(especially play action passes) more effective than normal. More YAC comes with an effective play action game. So you do not have to win a shootout. However having speedy wide receivers that get you an easy touchdown or two on big chunk plays is always nice. Remember the bowl game that Zaire quarterbacked against LSU. We absolutely controlled the clock to win that game but that Fournette guy was so spectacular he almost pulled out for them himself. They had far more speedy talent even though we had Fuller then.
When we had Rocket and Watters along with the powerful line and very strong defense we could have beaten the Giants and Jets on the same day. I exaggerate but you know what I mean. We had team speed and the ability to control the clock. And Rice was a super runner who could run out of tackles like a running back.