I think writing notes helps us remember things because we're concentrating on the information being recorded, and because in order to record it we are forced to create a well structured representation of that information which will also be easily remembered.

However, when I take a picture, I'm mostly concentrating on the camera and the spacial aspect of what I am photographing (getting it into frame), which doesn't help me remember any of the details, which are the genuinely important bit.

I do like your explanation though. I wouldn't be surprised if people who are more (for lack of a better word) artistic than myself, focus more on the details as part of the photo-taking process, and so retain those details better.

Trying to actually get good at photography is slowly teaching me to see- I see animals I didn't before, I see pretty compositions that didn't register before.