A Voicebot is a Chatbot that interacts exclusively using voice, while Chatbot is a more generic name for programmed communications using voice or text.
Many people prefer the conversational style of interaction with a Voicebot. Voicebots are well suited to applications where the user may be driving or otherwise multi-tasking.
Building out a chatbot using Facebook Messenger or Slack will not integrate it into your existing technology. You will need a chatbot platform and programmers to integrate it across multiple channels and into your current platform.
Chatbots are well suited for certain tasks; customer service and marketing among them. Chatbot technology use is growing in many sectors, including banking and writing content.
Data training teaches your chatbot about your business, so that it is able to build on that information and grow into a highly effective communication tool.