Worth is very subjective. And you're asking on a forum full of Aulani fanatics, so keep that in mind.
IMO, you should desire a Hawaiian vacation - not an Aulani vacation. Aulani is a very different experience than the parks or a cruise. Its a resort hotel with a subdued Disney theme. Its in an isolated area of Oahu. Disney planned the resort under the assumption that most of their guests would be transient with rental cars, off exploring Oahu for most of their trip. Because of this, IMO, there is not enough at the resort to keep you busy and entertained without leaving. Plus, I think its a sin to not explore the island after spending the time and money to go there. So, if you've never dreamt about going to Hawaii but are intrigued by Aulani, I don't think its worth it. But if Hawaii is a bucket list item for you, then do it and stay at Aulani while there. I hope that makes sense - all my opinion, of course.
There are ways to do it cheaper - you can rent DVC points for a cheaper price than what you'd pay booking through Disney. There are many brokers out there who facilitate this process, but you should be mindful that its usually non-refundable and you need to book at least 7-11 months in advance, so your dates need to be firm. You also would get free parking staying on DVC points. I'm of the opinion that a rental car is a must have there.
You could also stay elsewhere on Oahu for much cheaper - Waikiki, an Airbnb rental, other parts of the island. If you stay elsewhere, you can still visit Aulani for the luau, spa treatment, dining reservations. You can even use the beach and lagoon there because all beaches in Hawaii are public. You just would not be permitted to use Aulani's beach chairs or the pools.