I've always felt that the Federation holo-communicator used in DS9 exactly twice was such a missed opportunity! Every Starfleet officer can't have (or may not want to have, depending on the mission) any of their family or non-Starfleet close friends aboard their ship with them. It is of course important to bond with your crewmates, but Starfleet has always seemed to be very understanding of the fact that people appreciate being allowed to maintain relationships with those they knew before joining Starfleet, even allowing civilian families on the Starfleet flagship. It is possible to accidentally create a hologram on a holodeck that takes on a life of its own, so why should people in the 24th century be forced to settle for the closest they get to seeing their families while away on assignment be a computer monitor? It's such a shame they cut the device after only a few episodes! I know they did it for production reasons, but it would still be nice for Starfleet ships to have.