We took one Disney cruise when my kids were M12 and F10, and I definitely think it was worth it. Here are some things I liked (YMMV because this was awhile ago and Before Covid):
When the ship departs Port Canaveral, the checkin staff at the port run outside and wave to you with big Mickey hands. Coupled with the ship's whistle that played "When You Wish Upon A Star", it was adorable. Then there was a big Welcome show on the pool deck where Mickey and the gang did a cute performance and the kids got to dance with the classic characters! If you've been to Disney parks, you know that you're not terribly close to Mickey and company in performance. Here you were really close!
There were wooden deck chairs that had super comfy cushions on them. Very "Vintage Voyage".
I know a lot of people on this thread said the kids club doesn't compare, but I seem to remember that there were more organized activities for kids than on RCCL. When my kids were the age for the kids clubs, oftentimes Royal would have an activity in the Compass but when we stopped by the club there was no one there - no kids OR counselors! These were possibly off season sailings so there was less interest, but our experience with RCCL is that the quality of the activities for kids varies widely from ship to ship and time of year. It has never mattered to us, because both my son and daughter always preferred hanging out with myself or family anyway...
Which leads to my next bit, which is that we had some super fun family activities on Disney. One I remember was gingerbread house decorating, where each family was given a pre-assembled (real gingerbread) house and all the fixings to decorate it. Really elaborate candy for trimming, and a free activity.
Also, you couldn't head anywhere on the ship without running into Belle or Alice, etc. It was neat to just stumble over characters as if they were also guests on the cruise, rather than the more regimented lining up to meet characters at the Disney Parks. On formal nights Mickey and Minnie were wearing a tuxedo and a gown! When we went to Disney's private island (pristine, lovely) I actually saw Goofy in an old fashioned kind of swimsuit leading kids in games. Yikes, that must have been hot! But cool to see a character in the wild, so to speak.
I don't remember any more kids than on RCCL. There was an entire entertainment district that kids aren't allowed to enter at any time, so no Timmys or Sallys at the bar at 10 PM! Which actually meant less kids around in adult venues.
The entertainment was terrific, the equal of the shows in the parks. And one was a areal tearjerker, if I recall. The food was also great, and their concept then was that you went to a different restaurant each night (twice if on a 7 day cruise, which we were), and your wait staff followed you from restaurant to restaurant! One night was like a tropical restaurant, one was a stark restaurant with black and white illustrations of Disney characters on the walls and the waiters' vests, which slowly got 'colored in' over the course of the meal. (The waiters ran 'offstage' to flip their vests to a colorful side right about dessert time when the walls had also exploded into color), I can't remember the third restaurant, but there was a fine dining restaurant that you could visit once per cruise that cost nothing extra. (Adults only.)!
Speaking of our waiter, he was one of the most engaging we've had on many cruises. A Frenchman, he was saving up to go back to France and open his own restaurant, he was dating Belle (!) and he literally hand fed the kids escargot which they ended up loving.
It was a quality cruise and I'm glad we did it. However we never returned because it WAS so much more expensive than Royal. We also have sailed Carnival a couple times and there were some nice touches there, too. For me, Princess was one and done also. All and all, RCCL was and is our overall favorite!