For example my thermostat goes up to 85 when I'm not at home, and I set it to a more comfortable temperature before I head home (it'll automatically get more comfortable when I arrive, but on hot days it's nice to pre-cool). You could accomplish something that works maybe 90% as well with lots of effort and a programmable thermostat, but this is more or less automatic.
My entryway light turns on automatically when I get home
I can turn off the lamp upstairs while I'm laying in bed, without having to get up.
Through HomeAssistant (HA) I have a spoken notification to remind me to run the dishwasher right when the electricity time-of-use peak pricing ends each day. It also flashes a light a specific color when it says it so even if the tv is on loud, it'll get my attention.
HA automatically turns on my desk light when my webcam turns on.
HA allows me to remote-start my car with a Siri shortcut, instead of having to dig through the terrible manufactures app.
HA lets me know if I forgot to lock the door to my house.
I also use Alexa to fake lights being turned on throughout the house when I'm away for an extended period of time, so the house doesn't seem as empty. There's a HomeAssistant extension that will record normal behavior in your house, and replay it on demand, which I'm thinking about using to randomize the lights even better.
I had it come on in the morning before I get up, then turn off after I leave for the day. Turn on in the evening, and off at bedtime. You can get mechanical timers for that, but they don't adjust themselves for daylight savings or changing sunrise/sunset times. I was going to set it up to stay on longer when it is dark and overcast out, but I moved to a place with better switch placement, so never did.
The selling features are the boring things. Like connecting a light switch to a lightbulb without having to pull wires through external walls. Or instead of waking up to an annoying alarm clock wake up to your blinds opening.