a) Allow the controller to have a complete copy of the flipbook, as far as it goes (and review it) during play. Also prevents loss of the flip-book if the player disconnects.
b) Allow spectators to watch the book being written.
Probably easiest to have this use the same port as SiD, since this saves the player from opening yet another port (and they probably have it open from controlling anyway).
This would:
a) Allow the controller to have a complete copy of the flipbook, as far as it goes (and review it) during play. Also prevents loss of the flip-book if the player disconnects.
b) Allow spectators to watch the book being written.
Probably easiest to have this use the same port as SiD, since this saves the player from opening yet another port (and they probably have it open from controlling anyway).