I have no idea what the product manager was thinking here... Can someone elaborate why this "feature" - which implies potentially a lot of confusion - benefits most users?
I can't help but notice that slack is starting to get "enterprise" (threaded comments, this username thingy, ... ). They seem to be introducing a lot of complexity for all of the users, while only some of them would benefit from these new features. I'm hoping that they start realizing this, and keep simple chat the default, while allowing you to opt-in for all these "handy" features...
Wow, "it's more convenient for us to scrap usernames rather than re-think our system" ... I love you Slack, and I also don't understand how you are where you are.