* Turning on/off lights
* Changing the thermostat set temp
* Asking about the weather forecast
* Add items to a shopping list
* Playing music
If you can't imagine a voice interface being appreciably better than a phone interface for these things, I recommend withholding judgment until you've tried it.
Also, to be very clear (since some people have a knack for arguing points I never made), I'm explicitly not saying that the current hot-mic implementation is technically necessary or ideal, nor that these conveniences justify the privacy tradeoff.
Obviously not every action is easier or more optimal by voice, but having the option is great.