For people like you and me, the only reason for contacting support is when a human decision is needed, ie the UI doesn't allow us to do what we need. This is always the company's fault, and a chatbot is of no use in these cases.

But many people will contact support instantly when they think of something, no matter what. Even if the website and other customer-facing material is crystal clear and has all information necessary.

AI chatbots is the way a company deals with the latter, because these customers most of all want a conversation. The question is if they will be satisfied with a robot, or still demand to talk to a person.