This extra priced event (currently $45 per person) is not billed as actually having a purpose other than having a dessert and hanging out at a great location.
You are seated in retro comfy chairs and couches..and hey, they light up. It is very cool to observe all the goings on in Tomorrowland from high above the crowds. When I was there a band was playing at Tomorrowland Terrace Stage, so added bonus.
There are light sabers to play with and some games. A character or two will visit. You can hang out from 8:00 -10:00 pm. Is that it? Pretty much. Unless there are fireworks scheduled for that evening (and they aren't cancelled due to wind or some other reason).
I found it a very nice way to spend an evening and a welcome escape from the crowds. Great snacks and fireworks from a different viewpoint added to the enjoyment. I give it 4 churros out of 5. Enjoy!