Without knowing that product well, I think the main difference is that HelpHub is not just a ChatBot. It's also a full in-app help center with semantic search etc. The ChatBot integrates with the rest of the features and among other things links you to the sources it used to generate the answers.
How do users who can't find an answer get an answer from support?
HelpHub has a way to add a large CTA for that as a fallback. E.g. our own HelpHub implementation has a _Message Us_ button in the bottom to trigger a chat with a human support agent.