There are no other advantages to the deluxe rooms. They are just a bit bigger. (Not a lot bigger, just some.) They are on higher floors (5 & 6 I believe), but personally I liked being lower and closer to the animals.
Depending on the ages of the kids, consider requesting bunkbeds. It gives you a *little* extra floor space in the room.
Basically, unless you need the day bed, I'm not sure I could justify the extra cost of the deluxe room for myself personally.