I've been doing home automation for awhile now. Voice assistant is never anything I would consider. What problem does it solve that a button doesn't do with less hassle?
Also, note automation. The whole point is for the house to do its thing with minimal interaction based on triggers and states. Everyone leaves? Turn off the lights, lock the doors, turn down the heat. TV comes on after dusk? Dim the living room lights if they are on. Going down the basement stairs? Turn on the lights. Cat just used the litter box? Turn on the hepa filter for a bit.