I have a workday routine setup to turn specific lights on for set stations. If my bathroom vanity and kitchen lights were capable of taking smart bulbs, I wouldn't have to touch a light switch in the morning. It also means I don't have to fumble in the dark, half asleep.
I also have another similar routine but for when my wife gets up with the kids for school.
Being able to let the kids keep a light on but at 1% brightness is glorious, because it's a nightlight they can't pull out of the wall.
Mood lightning in not just brightness levels but also colours.
Granted half of what I said is capable without a voice assistant.
Also I discovered that simulated grey light is a thing and it's awful... But I learned that because of my voice assistant.