Thanks for the question. The Pega Customer Service 7.22 release extends the Intelligent Virtual Assistant Facebook Messenger capability in the platform to provide a chat escalation option. The chat isn't handled within the chat CSR UI in the CS interaction portal (largely because we need to support some content types (buttons, links etc) in the Chatbot transcript that is transferred to the agent that Pega Chat currently doesn't support, but in all intents and purposes it is a full feature chatbot to chat escalation option in our Customer Service app, and does require the licensing of seats with PegaChat access to utilize.
So - yes. I wouldn't recommend attempting to build an entirely new chat client of your own, but if the chat channel within Customer service is an option for you, then you should have what you need!
We'll start adding a number of bot and AI features to PegaChat in the very next release of the Customer Service application (7.31). Its going to be a Fall 2017 release - exactly when TBD :) We are working hard on wrapping up the release as we speak :)