Is it worth the investment?

no

I thought it would be a slam dunk and a good transition for my kids (6 and 4) since at the time Moana was being watched a few times a week.

Nope

I put a show on and once it is over they switch back to netflix. I am not sure if the algo's or UI, but they prefer netflix.

As a family we use it for movie nights and the wife and i like mando.

As far as right now, it may not be worth it for you. But I think that will change.
1) They are behind on rolling out the adult oriented content due to covid
2) A short while back (due to covid), the company as a whole pivoted where they are going to focus more on Disney+ as opposed to the theme parks. So I think we are going to start to see a lot of adult oriented content produced just for Disney+ to keep viewership numbers up. A lot of this would come from Star Wars and Marvel. So if your into that, I would say in 6 to 9 months, you will start to see more of that available.

I did a three year sub to Disney+ when it came out because my kids were 3 and 6 months, plus I was looking forward to Star Wars and MCU content. We watched it a lot (for how much tv I let the kid watch) for awhile. Now I use it mostly.

Depends on the family. For us, it's worth it for the Marvel stuff alone.

If Disney +, we find it well worth it. Classic Disney films for the kids and shows from Disney Channel. There are some good family films and nature documentaries we can all watch together, and for us we watch a lot of the Marvel/Star Wars films.

If you ever want to see a couple Disney princesses get it on check out Wild Things on Disney owned Hulu.

what do you mean by "investment"?