This is rather cool though from an implementation point of view. I actually wrote my own really cheap chat-bot a few years ago, and its surprising how far you can get with a few simple techniques if you know exactly where you want to direct the user.
A while ago I was working at a client site where there was an internal discussion group about building a chat-bot. Many meetings had passed, discussing using neural networks, building flows, should we use IBM Watson. Lots of talk, but not much delivery.
During the next chat-bot discussion while it was happening I during that meeting wrote and showed at the end a chat-bot that was further along than anything else delivered, not hard considering they were still talking. Code is here for those interested, but please don't judge my hour worth of python too harshly https://github.com/boyter/really-cheap-chatbot
Example flow of it
Hello! RCC (really cheap chatbot) here what are you trying to do today? At any time type quit to quit.: pay bill
Do you want to pay your bill using a credit card or using paypal?: dunno
Sorry I did't quite catch what you were saying. Could you try typing it using different words please.
Do you want to pay your bill using a credit card or using paypal?: credit card mate
You can pay online using your credit card at https://plumbus.com.au/pay