I just had a use case the other day: my mom sent me a photo of a handwritten recipe from my great grandmother a year ago. I only remembered asking about asking, not about the response, so I was happy to still have that pic in my history. Had I downloaded the Pic, it would be lost among all the other crap I store all ocer the place. This way it was preserved with the context and even a voice message from my grandmother (not great grandmother) remarking on it.