I'll barely use it if it's included in an annual pass but I don't value the service that much. I prefer to take lots of pictures when visiting the parks with friends, but when I'm by myself, I keep it pretty low key and also don't post about it on social media. Or I'll just take phone selfies. For some reason, I've always objected to paying inflated prices for photos (so the savings off the a la carte price isn't a factor here).
Then again, I have a friend who learned about the service and was very excited about using it on his next trip. He likes to take lots of photos and enjoys the idea that someone with a professional camera can capture key moments. He also likes character greetings (which I'll skip on a solo trip), and I think this enhances that experience as well. The Disney photographers are also great at creating magical shots -- where the photo is augmented with additional fun characters or action overlaid.
So the unhelpful advice is that it definitely depends.