Start with chat when the process already exists and the main problem is usability
If the team already has a relatively stable knowledge base, rule base, or processing path, and users mainly struggle because the system feels too rigid or difficult to learn, a chat interface can reduce adoption friction in a meaningful way. In that case, chat is a more natural interaction layer on top of existing capability, not a substitute for missing process.
Good examples include internal knowledge search, standardized information lookup, report explanation, routine support triage, and other scenarios where the underlying logic is already fairly well defined. These projects are usually easier to make useful in a first release because the model is not being asked to invent the operating structure on its own.
Underlying knowledge or rules are already fairly stable
The existing system works, but ordinary users find it hard to use
Question types are concentrated and answer boundaries are reasonably clear