Sounds like a generic botnet along with TVs, app based home cameras, routers and such.

Anyways, I remember some old story I've read, not idea if true or not, but someone was going over .sh files of a past employer and one of them telneted into a coffee machine (that reportedly nobody else knew had telnet) and made it brew coffee in just the right timing for the person to walk there and put a cup in the machine for coffee to start pouring right away. I guess that's one actually good use for a "smart coffee machine"... Or they could wait. Unless they are paid hourly and the coffee break isn't included, somehow.