Most Slack integrations are essentially first-generation chatbots (parsed and tokenised text input linked to a finite state machine to actually do things), and they're hugely popular among users. I see Microsoft and Facebook's moves as bringing those things to a wider audience - instead of telling Hubot to deploy some code using Slack we'll tell a brand we've bought something from that an order has been delayed using Facebook.

People already seem to prefer to interact with a brand using Twitter than the phone. There's no reason why many Twitter interactions need a human being behind them.

Chatbots are essentially Blade Runner for customer relations. Sort of.