I'm not sure if this service specifically requires full access permissions or not, but I do know a ton of these (awesome/neat) plugins like this popping up require a company to give the plugin full write/read permissions. And for that reason, it's stopped our company from being able to use them. I'd be curious to see how many companies would actually allow a 3rd party service to have that full amount of permissions.…
Run an IRC server, configure a hubot. Yes, 'cloud'-based chat is pretty, but it's a new coat of paint over something that's been around for decades (IRC). For a company less than several thousand people, running your own singleton IRC server is about as complicated as setting up a basic 3-tier web application (i.e., a little fiddly, but not hard at all)
Slack, Hipchat and others however can be easily set up and used by pretty much anyone in a company. IRC is great for companies which only have very technically proficient employees, however that's not most companies...