the obvious is private, 100% local alexa/siri/google-like control of lights and blinds without having to conform to a very rigid structure, since the thing can be fed context with every request (e.g. user location, device which the user is talking to, etc.), and/or it could decide which data to fetch - either works.

less obvious ones are complex requests to create one-off automations with lots of boilerplate, e.g. make outside lights red for a short while when somebody rings the doorbell on halloween.