> isn't the most convenient way to turn on a light switch still just physically flipping the switch?

The answer to this is: No.

The Echo and Google Smarthome don't require you to take it out of your pocket to interact with it. Walk in the door and it's listening. It sounds like a small difference but it is huge.

I think voice interfaces are very easily dismissed as for the lazy people, or a gimmick. Until you start using it on a daily basis. Then you start to realize how stupid it is to not be able to turn on your lights while both hands are overloaded with grocery bags (because two trips to the car is just never done!)