A chat box is not automatically the right interface. It is excellent for open-ended, exploratory work and poor for repeated, structured tasks, where a form with three fields is faster and less error-prone. A great many products have adopted chat because it demonstrates the technology rather than because it suits the job.
Technical view
Chat imposes high articulation cost, since the user must express intent in prose, and gives no affordances indicating what the system can do. Structured interfaces reduce both. Hybrid patterns work well: forms or controls for the common path with natural language available for the exceptions, or natural language input that resolves into an editable structured representation the user can confirm.
Related
Part of AI Terminology Index, section: Product and Adoption.