Yes, witty banter is a plus. But, the ultimate mission of a bot is to provide a service people actually want to use. As long as you think of your bot as just another communication channel, your focus will be misguided. The best bots harness the micro-decisions consumers experience on a daily basis and see them as an opportunity to help. Whether it's adjusting a reservation, updating the shipping info for an order, or giving medical advice, bots provide a solution when people need it most.
Chatting with a bot should be like talking to a human that knows everything. If you're using a bot to change an airline reservation, the bot should know if you have an unused credit on your account and whether you typically pick the aisle or window seat. Artificial intelligence will continue to radically shape this front, but a bot should connect with your current systems so a shared contact record can drive personalization.