The fountain is worth a stop. I wouldn’t go to the center just to see the fountain, but if you’re at the center for any reason then you should stop and check out the fountain. Of course if you got your bathing suit or kids, and it’s a nice day, then you can bump this up a notch on your “must see while in Seattle” list. The kids have a great time running through and playing on the fountain, and it can give you a chance just to take in the scenery and rest your feet before heading out to the next goal on your list.