Personally, I always suspected the Black Pot region of this bracket would come down to these two. If you ask the average person anywhere in America, these are the dishes they'll probably mention if you ask them to describe Cajun cooking.
Jambalaya is No. 1 here for a reason. For one, it's probably the most ubiquitous dish getting cooked across LSU's campus on any given gameday. It's relatively simple and hard to screw up -- again, if you can cook rice, you can make jambalaya. That simplicity lends to it being incredibly adaptable. You can put your own twist on jambalaya a lot of ways, whether it's a change-up of the meats involved, seasonings, liquid for steaming the rice, seafood, what have you. And on top of that, it's one of the more cost-effective ways to feed a lot of people, because rice tends to go a long way.
On the other hand, gumbo includes those magic words. "First, you make a roux." And when it's done right, it's definitely the more luxurious food item. However, it's also best served in colder weather. The thought of gumbo on a warm September afternoon isn't all that appetizing, especially out in the sun on gameday. Plus, gumbo is always better on the second day, so you're better off cooking it the night before and just warming it up on site.
But likewise, gumbo has versatility. Chicken and sausage, seafood, or your favorite wild game. Hell, you can even go vegetarian if that's how you swing.