Bro Zeke ran for 230 against Bama and then 246 yards against Oregon in the 2 playoff games lol. He had 56 Carries for 476 yards in those 2 games himself lol. Cardale threw 2 TDs 2 INTs and ran the ball 38 times in those 2 games lol. And they had Michael Thomas, Curtis Samuel, and Devin Smith was good that year. He was fine lol. Did he do more than Emory could? Yes. But primarily they ran the **** out of the ball to 8.5 ypc with Zeke, then He ran the ball, and then had some easy passes.
Now I will say having a guy who is a legit run threat as a backup is very nice for just that reason. You don't expect your backup to be great throwing the ball, especially if inexperienced. But if they can run, it really helps you out, and makes it easier to win that game or two you need them.
Also, Pre-NIL Roster construction is pretty irrelevant to how it's setup today.