IMO, most chat bots out there are just digital reincarnations of phone VRU systems. I don't see them taking over customer support anytime soon. Bots should not be the front and center of customer support, but should be assistants on the sides of both customer and the support agent to provide sideline help while a conversation is ongoing, instead of the bot taking over the role of the support agent.
For example, when I start a conversation with a support agent, I could be prompted to enter my email address if I havent, or select a category (shipping, refunds, etc), all while waiting for the agent to get back to me, or as a starter to the conversation. On the agent side, a bot could be helping me by suggesting responses to the customer's question and letting the agent pick a response, instead of the bot answering the customer directly.
The human experience is crucial when dealing with a business. We're not there yet with AI to have bots take over the entire conversational experience between a customer and a business, so if you're building a chat bot, please don't bring the horrible phone VRU experience to the internet.
Don't get me wrong on bots though, they're awesome when it comes to certain situations and tasks that don't require human to human interaction and are usually structured, like shopping. Take Shopify's Facebook Messenger bot where a person could shop on a business's Facebook Page via their Messenger bot, with the bot taking on the role of navigating the catalog for the user.