I do not believe that a photographic memory(or more accurately, the popular definition of the term is, eidetic imagery)would be useful. Imagine not being able to forget graphic images of violence in the Middle East(for example), once you see it on CNN with your photographic memory.
BUT what would be useful, is to remember ANYTHING you want, ANYTIME you want, at will, i.e. simply by willing that memory to surface into consciousness. So your memories, whether it be a fact, image, word, sound, experience, feeling, will only surface if you will it. And you have complete control over every aspect of the process, from the level of vividness, clarity and precision of the memory, to appropriately suit your level of comfort with that memory(hence, useful in NLP).
