From NN/g: https://www.nngroup.com/articles/chatbots/
Summary: Far from being ‘intelligent’, today’s chatbots guide users through simple linear flows, and our user research shows that they have a hard time whenever users deviate from such flows.
The chatbot is the poor relative of the intelligent assistant.
Elsewhere , we discussed the 6 qualities of an intelligent assistant: voice input, natural-language processing, voice output, intelligent interpretation, agency, and integration of all the previous. A chatbot needs to possess only two of these attributes: natural-language processing and intelligent interpretation. In other words, a chatbot should be able to receive queries in natural language, and also understand and interpret them correctly (and then execute them).
In today’s world, chatbot growth and popularity is motivated by at least three different factors. First, there is the hope to reduce customer-service costs by replacing human agents with bots. Second, the success of conversational-based systems like WeChat has put forward the idea of chatbots as an interaction channel with businesses and services, intended to supplement existing channels such as the mobile web and mobile apps. Last, the popularity of voice-based intelligent assistants such as Alexa and Google Home has pushed many businesses to emulate them at a smaller scale.