What do you guys think of the idea of smart homes? I could make a basic setup using https://home-assistant.io to control my home temperature and lighting; the tools for doing this are everywhere nowadays and implementation doesn't seem too horrific anymore.
But setting aside what I "can" do, is this something that I "should" do? How can a person implement this without connecting any devices to the internet?
As others have said, you can sequester IoT devices to a VLAN that has no internet access. Most of the common devices (lights, switches, sensors) added to smart homes work perfectly fine without access to the internet. Voice assistants are the biggest security/privacy hole since all commercial options are from big tech companies and phone home constantly. If you set up a local homeassistant instance you can get a ton of functionality out of smart devices with no direct connection to the internet. You need to decide how you handle accessing homeassistant from outside your home if that's something you want but there are plenty of options to choose from for that.
One thing I will say that I refuse to add to my home is any kind of smart locks. No matter how much I trust my security setup, I don't trust it with the ability to unlock my doors. If there was one that could only lock them electronically but required being manually unlocked, them maybe. But I haven't seen a lock like that out there.
I just wanted to add that I'm very glad smart locks exist. My friend with cerebral palsy can now secure his home with a lock and be able to get back in independently.
In general, smart devices are huge for him, and others with physical disabilities.
Also, I should say that I really enjoy the convenience of having Google Assistant in the house. Verbal timers, alarms, reminders, podcasts, and music mostly. Those and the pirate FireTV Stick are our only devices to date. I just don't care enough to put the legwork in to getting IoT set up. Switches are fine.
That's great that they help your friend like that! As someone that doesn't face any kind of accessibility issues myself, it's easy to overlook those kinds of benefits that these devices can provide. In situations like your friend's, I'd agree that any potential security cons are outweighed by the pros (especially if the alternative before was having to leave the doors unlocked anyways).
Agree on the convenience of voice assistants. I've got various models of Google homes in my house that I use for voice controls on anything I don't have a good way to truly automate. Different people will have different tolerances for how okay they are with the data things like that can gather. One day I might try to set up one of the local network voice assistants but those can take a lot of work to get just right. Always a tradeoff of convenience and privacy.
Oh that's interesting. Does Google Home work on an unconnected VLAN for lights? I use it for lights and kitchen timers. I don't see myself adding anything more complicated or invasive though.
I don't think Google home would work without an internet connection. I believe google devices and the google home app expect a connection to Google's servers.
I personally use homeassistant to control everything without an external internet connection and I know you can lock Philips Hue lights off from the internet and the official Hue app will still work.