In addition: Atlanta is the "center" of college football. Heck, UGA actively promotes being "near" Atlanta. Bama sells to recruits that they will get to play in Atlanta multiple times during their career.
If we can steal their thunder a little or piggy back off of it, then it is great. Eventually, we want it to seem silly to recruits that UGA claims to be "near Atlanta".
Also, I think the secondary purpose is to try and make GT Atlanta's team. We aren't going to sell out the stadium with the current GT fanbase and/or alum. We need to get people from Atlanta without a college team to be GT fans and come to the games.