That the organisers enjoy themselves. There will also be specialist objectives, specific to each event. Everything pales into insignificance by comparison with the players being satisfied. This may be that they make money from the event. But few are in chess solely for the money.
Many organisers fallaciously believe publicity matters little without sponsors.
We are fighting for our place in a competitive market against other leisure activities. The steady drip of publicity can be extremely effective. In addition, the players will be happier if the event seems important and are thus likely to return. Gone are the days when sponsors were satisfied with a crumb of publicity. The are entitled to everything that can be wrung from the event.