The tournament is a little convoluted. Having to pick types, then get a party back, and then maybe having to reshuffle (not to mention having to track down very specific Pokemon) is quite a bit of prep work for a wi-fi tournament (and wi-fi tournaments have plenty of prep work as it is, which is the principal reason they don't get as much turnout as we like...).
As far as your different note goes, you don't need to be a Tournament Director to host tournaments. Anyone can host a wi-fi tournament as long as said tournament is approved by the wi-fi mods. If you want to know more about the Tournament Director badge, feel free to contact my fellow moderator Ditto, who is our wi-fi centric Tournament Director.