It's certainly pretty. It reminds me of that quote by Joel Spolsky - "people ridiculously overvalue aesthetics and beauty when evaluating products. It's one of the reasons iPods, and, for that matter, Keanu Reeves, are so successful."
I don't think usability-wise it's all that great though. If you have multiple chatrooms in multiple slack organizations, it's a PITA checking on them all, for instance.
Engineers undervalue it, users overvalue it compared to other criteria. Mostly because users are not engineers and so have no way to look at why a product is engineeringly superior; they can only look at how easy/simple it is to use.
I don't think usability-wise it's all that great though. If you have multiple chatrooms in multiple slack organizations, it's a PITA checking on them all, for instance.