If you expect to go to a water park at all, it makes sense, because that's less than the cost of the water park entry. It's also in the neighborhood of the mini-golf and DisneyQuest costs, so if you're possibly doing any of those things, it seems to make sense to me. When I read that the cost was so little, I added it without question. I'm planning one water park day, and even if we only do that, it paid for itself. The theory seems to be that they're hoping to spread out the park crowds more by encouraging people to do the water parks, mini-golf and DisneyQuest, so they are all but giving it away.
The only thing that gave me pause was in considering a possible upgrade to AP, because if you have WPF&M and you upgrade to AP, you have to get Premier, which is a good bit more expensive. If you won't use more than a few of the WPF&M entries in a year, it stops making financial sense when you might upgrade to AP.
°o° Lace — Planning our second WDW adventure, 11/1-12 AoA-LM (Sent from my iPad using DISBoards)