Sometimes, as a website owner, you may be wrong regarding the kind of information visitors are looking for. A bot can be also useful here (people not finding what they are looking for may ask the bot, the bot probably won't be able to answer but, if you're using a decent bot platform, you'll be able to easily get a report on what questions people are asking and then add this either to the bot or to the website if you prefer).

In this case doesn't your customer walk away frustrated at best, after a nonsensical conversation with a bot? That's been my experience every time. I ask a question, then the bot asks me questions that are irrelevant and make it very clear it doesn't understand what I'm saying and that I'm not talking to a real person.

That’s a reasonable point, but I would argue that the same could be accomplished (with a better user-experience) with something like a “Not finding what you’re looking for, click here” shown on the website in the appropriate places that leads to a contact form. When you end up talking with a chatbot you have no way of knowing if it doesn’t have access to the information you’re looking for, or if you just haven’t asked it using the right key-words or terms. That can make it a significantly more frustrating experience then just using a contact form and waiting a day for a response.