When I'm thinking genealogy, and doing research - I'm not sure I would want to see pets or photos that don't relate to the task at hand, in addition to the ancestor photos, census/records images etc. Some profiles are quite 'busy' as it is.
It might eventually lead to a lot of clutter on a site that's dedicated to genealogy.
Have to think more about this idea... but I'm thinking those kinds of things are best if they remain on the Private list.