Well for one there is no general, seen by all, chat room with this new chat. Users can make a room, but then it is only visible to the people that are invited to it, and not to the general group of forum members. So who knows how many private rooms there have been made in this new chat. But I can say there are no public ones, and that is the reason it doesn't really work. I can sit in my created room and invite people that I see online, but that is tedious and more attention than I can pay to this site just to have some chatting going on.
It is just an invitation only instant message system, and not an open chat room. So it doesn't work as a chat room.