I guess it depends on what you consider "worth it" for you. What do you hope to gain by going there? Is it the prize money? Maybe you think you've got the game to contend for one of the top placings in your section, and maybe you do. But it sounds like you've never played in one of these tournaments, and it's a whole different venue than a small weekend swiss. These events do attract sandbaggers. There's also a higher incidence of cheating. People who haven't got a clue about etiquette in the playing hall can be disruptive and disturb your concentration. Organizing these events is a tough job. Just keeping things flowing smoothly is quite a challenge. When things get out of sync, it can be distracting. You might play up to your usual standard through this type of atmosphere, but don't count on it.
If you want to try one of these tourneys, I recommend you just suck up the expenses and give it a shot for the experience. If you win something, fine. If not, see what you can pick up in terms of chess knowledge. A lot of post game analyzing goes on at these things, sometimes with input from really good players.