Hi Ashley. My family and I are big fans of these special Magic Kingdom events like the
Christmas and Halloween parties. First, you have the unique parades and fireworks. Plus, the tasty treats, like free cookies and hot cocoa, are my kids favorites. The other added benefit is that the park is closed to other guests and I have found that all the best attractions are open with limited lines. What often would take me hours to cover, my family and I are able to complete our favorite rides in far less time.
With that said, yes, it is an added expense that may not be ideal for everyone. The key question is whether your children, being a bit younger, are up to late night ventures around the park. If your kids tend to be tired and ready for bed towards the end of the day, it may be difficult to take full advantage of these events. Should you be interested, I would recommend either a mid-afternoon nap or a relatively quite day otherwise so that their energy is conserved for what is a really fun night. Enjoy your trip!