Well, it's ultimately going to be up to you if it's worth it or not.
I will say this:
1. A seat is pretty nice, instead of jockeying for position with 100's of your closest friends, (and then, once you have the perfect spot, having someone shove their way in front of you, and put their kid on their shoulders.
2. It's more than desserts. I easily made it a filling dinner. Not a very healthy dinner, but I pigged out on the cheeseburger egg rolls and spinach dip, and chocolate covered strawberries.
IMO, the piece of mind for having a great view, and dinner, is worth it. I saw the fireworks show as a kid a few times, and mostly remember standing for 15 minutes and seeing a few fireworks and mostly butts and shoulders. Now as a family man with a little guy, and a petite wife, it was WELL worth it for us. We had a GREAT view, and relaxed the whole time, with FULL bellies.
The Star wars one is even better, but the one at MK was worth it for us. If you think you can make a dinner out of what's offered, take that into consideration. It was PLENTY for us to make a dinner out of.