I got it for about $12 less through a different seller than Origin but even if I had paid full price, I would feel as if it were worth it. Heck, forty dollars equals two trips to the deli for me and my S/O; it's the price of one dinner at a very special restaurant my family and I visit a couple of times a year for special occasions; it's less than half of what it costs to get my hair cut and highlighted every six weeks.
For me, the new world, mermaids, interaction with dolphins, expanded fishing, and build items were definitely worth the asking price, not to mention that island view. My real life is sometimes so stressful that coming home in the evenings and watching my Sim fishing from her boat with a Sulani sunset in the background is super relaxing.
I know not everyone has as much money in their budget as I do, but I will get literally years of enjoyment and relaxation out of this pack. I play this game at least four evenings a week, for a few hours at a time, and when I do the math on what it costs versus how much time I spend in the game, in the long run it turns out to be inexpensive entertainment indeed.