If you think about them as advanced search engines that pick up your question based on how the sentence is structured you can use them for following.

Customer Service -- Login issues -- Information about products -- Walk them through problems

Health -- Information retrival, pills, medicine -- Diagnosis, based on symptoms -- Getting an appointment with a doctor

Finance -- Payment, (entity wants to pay entity sum) -- Counseling (legal, tax, pension, savings, investment)

And there are a dozen more. Chatbots will work because they use an interface we humans already know well, natural language.