While I only have submitted scanned and edited images, I think there is a proper place for some photographs. This site is for cataloging cards and as a reference. Many chrome, prizm and other cards just do not scan. I would suggest a photograph is preferable. I submit many prizm parallels that scan nicely, but the base cards of the set are almost useless as a scan. I think the key with scanning or photographing is having some standards and encouraging those standards both positively and consistently.
Greg