I really like Intercom and here is an article from them about the future of chatbots with explanations why voice will be the dominant chatbot interface.

2016 showed us that texting chatbots is hard and takes time and effort. That’s why a lot of people right now tend to think that voice interface is a solution. But I think they are wrong. Good conversational design is a solution. As for me, I don’t see the voice to be the dominant chatbot interface, I think there’ll be more of a combination. While it’s super convenient to order a pizza with voice commands while driving a car, there are a plenty of situations when you don’t want to say something aloud.

I’ve shared a poll below to ask your opinion about this point, thanks for voting!

https://goo.gl/50cnEp