I have yet to see a bot client that did much for me. Most of the bots I see are merely news-search interfaces. They seem to supply a highly-curated list of articles, which I assume aligns with premium campaigns. I find this a belabored interface, compared with web category browsing, or web search.
For me, until voice-interface 'navigation' of the mobile device is a stable, usable, experience, then chat bots won't be a big thing. I think the killer-app mode will come when voice-UI works with chatbot-UIs that have symmetry with a websites main navigation system.
An extremely prettied-up and extensible voice navigation system like customer-support lines have tried for years. There are a gang of startups already trying to tackle this issue for the high-value targets of nationwide call centers.