Yes to the comfort aspect and the identification value. There's another use for family photos - when our family goes out somewhere public (the city, the Royal Show, etc), I take a photo of all of us together, as well as each child individually.
The individual photos mean that if a child is lost, we can show the relevant photo to police to assist in a search. The group photo also shows that we haven't photographed some random kid who we're trying to steal. It also means that if (hopefully when!) they are found, the group photo may bring them comfort.