The conversation only occurs in Facebook messenger. But there are a whole host of add-ins, you can connect it to different services. Another one to look at is motion.ai
There of course are also bots you can program from the ground up — but they obviously involve a lot more work. This was my go at looking at design and testing on a “chatbot as a service” platform.
Most services are open to ideas though — if you’re using one you can always say “it’d be cool if I could …”, and see if the idea is run with.