A QB that can run (not necessarily a running QB) simply adds another dimension to the offense. Despite Kirk's statement that offense is complicated, I will cite to an earlier oft-used statement of his, football is not "rocket science". A mobile QB requires the defense to pay attention to that threat, and in doing so, distracts them from other assignments they have. Simple, not complicated.
His passing stats in the bowl game are essentially meaningless, he was tossed into a no win situation. Tennessee figured that Iowa would do nothing but throw at that point, and Iowa did nothing to shake them from that belief. Here you go, Marco, I know you haven't played a single down up to now, and I know that you haven't spent any (meaningful) time practicing with the first team, and I know that we're going to line up in five wide with no additional pass protection without even a hint that we'll try something else, but go out and see what you can do with this pile of crap we've left you with. And oh, by the way, if you're not immediately successful in that situation, you'll be branded a failure, with no hope of improvement or possibility of success, by some. I'm not saying he's destined for greatness, but he deserves the reps this spring with the starting unit to see what he can do. We know what Hill can do, and we don't need any more of that.