If you think she will want to visit characters, it is absolutely worth it. Most (not all) of the characters have photopass. The photographers take several shots from the moment your child starts toward the character. Also, if you take advantage of it by stopping when you see photographers, you can get a ton of pictures. There are usually some photographers scattered around WS and we have gotten some great shots there. Also, with the park icons (Castle, Ball, Tree), be sure to take more than one set of photos. All photographers are not created equal. Sometimes you will get fantastic photos, and sometimes they are awful. Also, the time of day and where the sun is can really make a difference, as can the angle or closeness to the icon, especially with the castle. If you are doing Enchanted Tales with Belle, that will be a photopass photo (several if your DD takes a part in the play), and you likely will not be able to get a photo of your DD with Belle on your own camera in that setting. If you are sitting at the right spot, at the right angle you might be able to snap a photo, but we have been in there more than once when the7 instructed parents trying to move to get a picture on their own camera to stay seated.
If you are doing 7DMT, Memory Maker will get you a ride video. Also, if your DD is tall enough to ride some of the thrill rides, it will give you the ride photos. Some of our photos of DD on her first ride of things are absolute classics (yes, I am the mean mom that laughs at my child's clear terror exhibited in the photo). I think those ride photos are around $18 each without Memory Maker. I'm not sure whether 7DMT is even available without Memory Maker as that goes straight to your band if you purchase Memory Maker (someone else can tell you for sure).
The photopass photos are around $15 each if you purchase them individually. We usually wind up with close to 200 photos before edits, and we have wound up with over 1000 when I have done borders, crops, and saved some in different sizes to possibly print out and frame. There is no way I could have selected few enough to make it cheaper than Memory Maker. We get it every trip and we have never been sorry that we have done so.
I will say not to just rely completely on Memory Maker, but be sure to take photos with your own camera of your DD with the characters, and hand your camera to a CM to get some family shots. There are glitches and sometimes WDW does lose photopass photos. We usually lose at least one set of photopass photos each trip. In our experience, sometimes the photopass photographers photos are far better than the ones we take, but sometimes ours turn out better.