I've been using Home Assistant for a while now. I do recommend setting up a VLAN that can't communicate with the internet which is where any wifi devices live. However I really like ZigBee and/or Z-Wave devices as they don't require any internet connection.
Lights alone are a game changer. Timers never really worked well for us because we're pretty far north of the equator and sunrises/sunsets have a pretty big swing. I currently have the lights come on 1 hour before sunset so it adjusts to this swing without me having to do anything. Then I have a button on my nightstand that turns off all the lights that aren't night lights.
The downsides are that it can be expensive. You start with a couple of light bulbs, maybe a couple of outlets, next thing you know you are pricing out how much it will cost to change all your switches and trying to figure out if they all have neutral wires or not. You'll start watching youtube videos of people's setups and looking for ways to do more with your smart home. It's a fun hobby but can be a lot of work.
Agreed, 3-4 seems to be a sweet spot, 10 seems to be pretty much only for boiling water. 🤣