Actually you get all of that with an e-mail as well - services send you e-mails when something happens (which you can filter to different folders, you get desktop notifications and so on); you have a full history as well and at least at my company we have an "off-topic" group, which can be easily filtered out if you don't want to be bothered. To be honest a live chat seems to me like a bad idea at a company, because it just encourages people to spam. I don't know, maybe I just prefer an efficient use of simple tools.
You get that, but not in the same user friendly way. Plus email is passive, while chat is active. I think this is the main selling point of chat. With email you do not get the same feeling as a chat room, and maybe that feeling is what drives people to use Slack, Hipchat etc.
>Actually you get all of that with an e-mail as well
Things that "you get with technology X" by having to do 10 extra steps and have everybody else on the team do the same to get the same benefits do not count.
