I think it's kind of cool. Unfortunetly we had my mother-in-law's burial this past weekend. As I walked around the cemetery, we found family graves from 100+ years ago. I wondered what stories these people from 100 years ago could tell or even what they sounded like. Then I thought, 150 years from now will my grandchildren ever want to hear what their great grandmother sounded like. This sort of device could help retain a little bit of history.
But isam, you are correct. The technology would be obsolete way too soon. Any device would need to be self encapsulated and not dependant on a mobile cell or RFID reader.