We're aware that data is being piped in to a 3rd party system, so obviously some things don't go in to Slack.
An example of usage could be, we have a StatusPage.io site. Rather than subscribe everyone to email updates or similar that works here, and maintain that list, we simply have a plugin that pipes the updates in to Slack. That way if someone raises a status page update for a web server being down, everyone is aware that this is now public information on StatusPage.
This is just one of a lot of examples, but things like that once embedded become the norm quickly and you wonder what it was like before them.
