I did the add on, but it was slightly different when I did it (two years ago).
We stayed at the Marvel Hotel. However, we didn't have any meals provided (it wasn't even an option as far as I remember). We ended up just getting quick service or eating in Disney Village (Downtown disney equivalent).
I do agree that the full board looks like way too much food. I am not sure if you could select a smaller meal plan or no meal plan at all now.
Really, the only main advantage is that the transportation to
Disneyland and from Disneyland to the airport is included, so you don't have to worry about that. The transportation was pretty nice.
When we priced it out, the difference was pretty small, and I felt it was worth the cost. However, I don't know what it is now, especially with the meal plan, and how that works out.
The marvel hotel was really nice, recommend it if you are a marvel fan.
More than a third (close to a half) of the families on my tour did the addon (or at least went to disneyland after the tour was over), so no matter how you decide to go, I would definitely recommend it.
Please note that the Premier Access is not included. Before I went, the fastpass was included (if I remember correctly, it was unlimited fastpasses with no return time), but when they switched to premier access, they no longer provide it. Since premier access can be $100 per person depending on time of year, if you want to use that, keep that in mind.