If you take some of the public slack channels, campfire fits the better.

Look at Elixir's slack for example. Since it's a free tier, you can't view older messages that can be beneficial to someone. And Elixir's slack channel is not going to need fancy workflows, web hooks for CI, gitops capabilities et all.

Your expectations might have changed. Most users are quite happy with core chatting features. And in the case of Slack those features have become a bit too intrusive and disorganised, so that is one of the selling points of Campfire.