CariocaCoug says below, being a star at BYU AND in the world is better than just being a star in the world. It becomes a double benefit because of the brand that BYU already is in terms of a known association with the LDS Church.
How many people really associate Jabari with the Church? On a personal level, probably most, but on a general level, probably none. How many people associate BYU with the Church? Everyone.
This is why I would be a die-hard fan of BYU regardless of whether or not I ever had gone there as a student and why I encourage my kids to be BYU fans even if they never attend there themselves.