What if you aren't currently holding your phone, with it unlocked and the (probably slow to load) app open? What if you don't have switched outlets, and want to turn off lights either a) when the room is still dark, or b) when you're leaving the room?
Voice assistants are not a revolution in home living, but lets not go too far in the other direction and ignore that they do still have useful features.
Almost every instance of "useful features" described, yours included, seem much more like novelties than true utility to me. I get that this is the old man in me.
Same as AI. It's almost like we're scraping the bottom of the barrel for useful products, since capitalism demands people churn out endless useful products, regardless of whether they actually exist or not, so we're trying to make not-useful products into useful products to appease the machine...
I can generally speak to my iPhone and have it recognize and carry out what I say when it's still in its holster on my hip.
Anything that's set up in HomeKit is directly accessible through Siri, and IME most smart-home devices these days support HomeKit, even if they have their own apps as well.
So I don't need to have any app open, or my phone unlocked or even in my hand, in order to turn on and off the smart outlets I have in my house.
(That said, I also have a HomePod mini, because not everyone in my house keeps their phone on their person at all times—plus it's a nice speaker for the kitchen.)
Voice assistants are not a revolution in home living, but lets not go too far in the other direction and ignore that they do still have useful features.