Put simply: NO
The first thing I would tell you is that you DO NOT NEED TO BUY ONE OF THE PASSES—especially as a first-time visitor. The first time I was planning to attend, I worried about this and wondered if I should spring for one of the VIP packages at the Bourbon Pub, but please rest assured: you do not need a pass. Each venue has its own calendar of events for that weekend, and they each try to make it seem like you need a pass (guaranteed admission! No waiting in line!), but you can have a great time without ever attending any of those events. There are several websites claiming to be the “OFFICIAL” website, but that is just marketing. The official events take place in the streets and are free to everyone. You can simply pick and choose among the other events that take place over the weekend.
That said, some venues offer a pass that can save you some time waiting in line, as well as some money. Most of the venues charge a cover charge over SD weekend. Even the ones that are usually free or cheap begin to charge due to the overwhelming crowds. For example, Corner Pocket, a stripper bar with guys dancing on the bar, usually charges a $5 cover on the weekends. On the weekend of Southern Decadence, they might begin with $5 during the day (totally rough estimate there…they will adjust according to the crowds), but they might go up to $10 by 9:00, and they might be charging a $20 plus cover by 10:00 PM. And you may wait in a long line. As an alternative, they offer a weeklong pass ($40 in 2016, $50 in 2017) that guarantees that you get admitted without waiting in line. If you know that you are going to want to visit a specific venue every night, it could be worth your time to invest in a pass.