Kavli Frontiers of Science: is it a worthwhile use of one's time?
Yes, it's definitely worth attending and you should mention it to your dean.  (It's only a minor honor, but a minor honor is still worth highlighting.)  I did this some years ago, and it was a great experience.  Not particularly valuable for my research, but I met some fascinating people in other fields, some of whom I had more in common with intellectually than I had expected, and I learned many interesting things.