In a larger household, with many occupants it starts becoming more useful.
Simple things like roll-backs on lights for spaces that haven't been occupied 'for a while'. Or sensing occupancy and adjusting lighting and other conditions (shades, HVAC, etc). Note "occupancy" not just "motion". The lack of motion does not necessarily translate to nobody being present (sedentary use of a computer, watching tv, sitting in a bath tub, etc). Simple schedules to 'clean up' unused lighting or devices. Like turning off car/bike/power tool chargers if they've been running 'long enough'. Or activating them with simple voice commands.
Do you 'need' any of this? No, of course not, but it does add a bit of convenience for not a lot of technical implementation/cost.
Ac follows same logic. I have a scene called good night that turns everything including the tv off
What is wrong with the simple light switch on the wall?
Home automation sounds cool and all, but every time I look into it I realize that the switch does everything I need perfectly fine and doesn't have bugs. I'm not saying there are no uses for home automation, but most of them are overstated.