I can't think of a single compelling use-case for home automation systems. I'm trying to understand what other people see in it. I have to wonder if it's driven by the amount of interest a person has in "tinkering" with technology.
That said, I would never advise it for someone who doesn't like tinkering, or at least know how to tinker.
My favorite use case is simple, I walk into a room the lights turn on, I leave the lights turn off. I open the pantry door, light on, close it light off. I also enjoy getting in bed and the house shutting down, lights, security, temperature all tied to my wife and I just getting into bed.
Where people go wrong is buying light bulbs, well now you have to keep the light switch on 24/7 or the wifi bulk isn't on to know it shoudl be off? like WTH? Just automate the switch and use normal lights. Wifi anything (wemo, etc...) sucks and almost always requires cloud service, why reply on the company that sells a $5 bulb to stay in business? insane.
Maybe we're using different terminology, but what do you use in lieu of light bulbs? (I call any of those tubular things, e.g. fluorescent lighting, light bulbs.)
Then you can program anything to turn the light on/off. Like for example I also turn off lights even if there is motion if the luminance sensors say it is plenty bright inside from the sun.
Or leave the shower light on when the humidity is really high and there is no detectable motion. I might not be moving enough in the shower but if the humidity is 90% you can assume the shower is on and I don't want to be left in the dark.
Another one of my favorites is in our kids play room. On a school night, if the xbox is on, and there is motion, Alexa will announce a warning about bed time, wrap up the game play. Then in a couple minutes the xbox turns off, and then Alexas tell them to brush their teeth, and eventually turns off the lights in the play room (they would never turn them off on their own). If the xbox turns back on, my wife and I get an alert on our phones so we can manage screen time.
I can't think of a single compelling use-case for home automation systems that communicate with someone else's servers.
But, having lights and temp auto controlled would be nice. But getting a system up and running that only runs on MY server is a little more tinkery than I have time for what with all the LeetCode I have to do to switch jobs.
I love the feature that automatically detects whether I'm at home and adjusts the setpoint. This uses a sensor in the thermostat, put it also uses my phone's location, so arguably it is a smart home feature.
I also how it integrates with my phone at bedtime and when I wake up. I have a Google Assistant routine set up to adjust the setpoint when I dismiss the alarm in the morning. I also have a routine set up for bedtime which adjusts the thermostat and tells me what's on tomorrow's agenda. I like this better than a programmable thermostat with a set schedule because I don't always sleep at the exact same time, and it's annoying having my place get too hot or too cold before I'm ready for bed, etc.
I can't think of too many other use cases that make sense to me, though.
2. Start cooling down my house when I'm on the way home from work
I could attempt to set this up with a "dumb" thermostat but my schedule is unpredictable enough that the remote access helps me do it efficiently.