Yeah, Chatto should be relatively straight forward to use in "headless mode". I've seen a few users working on integrating it into their own applications as a chat backend.
Oh - that's interesting too! But I meant more as a frontend across various integrations a business might have. E.g. having a bot that tells you if your CI failed is currently likely surfaced inside Teams or Slack. Having an internal chat service feels like a big win so companies don't need to integrate private companies' tooling so deeply.