Because overall, it worked out just great for our family. We have always eaten one nice (ie: TS) meal a day while on vacation, and while an appetizer and a dessert per person is a lot of food for me, personally, we have two growing boys, who along with dh, were almost always able to scarf up the rest of my food. Our ds 12 was an adult on the plan, but he typically preferred the offerings on the children's menu, though he could eat more than the child's serving, so he often ate my appetizer. Our younger ds 9, was a child on the plan, but is more of an adventurous eater - likes things like calamari, sushi, etc. and though he usually ordered mac n cheese off the kids' menu, he loved to eat half of whatever I had! So TS worked out great for us.
Yes, we were full, but hey it's vacation!
As for CS - I'm not a big breakfast eater, but dh is, so we were often able to use 2 of our 4 CS credits for b'fast and 2 for lunch or supper. We just paid OOP for anything extra at any of those meals - no biggie.
Snack was the only thing we had lots of credits left at the end, and that was because not as much was included on the snack plan when we were there - basically drinks, popcorn, whole fruit and mickey bars. We got mickey bars twice, and water the rest of the time. We wound up getting lots of our snacks OOP - dole whips for ex. With the new and improved snack plan I doubt we'd have any Snack credits left.