The point of slack is that it is more than group chat, it's group chat that is easily extendable to your teams workflows. At my company we've extended it to support deployments, busting caches, executing jobs, etc. We've molded our project management processes onto it. It reports tweets about our company and it also reports errors in our infrastructure.

It's basically like a much-easier-to-extend IRC that is accessible to the mere mortal.