This is a great place to watch the sunset. Not that your kids will be interested in watching the sunset or anything, but maybe you will. Give them a bunch of money and ice cream and tell them you'll be back in an hour. That's what I do!
There's only a few places around the castle where you get a reflection shot. This is one of them. If you move around near the bridge in Tomorrow Land, you can go into the exits of the Lilo & Stitch ride to find this secret spot!