This is one of the reasons that smart bulbs and the like are generally bad - you never want a situation where the switch doesn't just act like a switch.
Smart houses should be designed from the perspective of remaining identical to use when the smarts go away. And if there's weird behavior it should all stop if you unplug the hub or controller.
I generally like in-wall smart switches but even there they tend to die faster than dumb switches, so you may be leaving your survivors a bunch of calls to an electrician.
Depends on your devices, but I have (Philips?) smart bulbs that can be turned on/off "regularly", but keep it on and you can control it via google home.
The main drawback is that this means I have to have the bulbs set to light up after power is restored. A middle-of-the-night power outage is fun when the entire house lights up at 3am :)
I've done a few new installs of lighting in my garage, driveway, and patio. Because that was "greenfield" work, I got to put smart switches in. If I ever rewire this house, I'll use that opportunity to do some more.
- "Everything 'smart' must continue to function if the internet is disconnected"
- "Everything 'smart' must fall-back to normal 'dumb' operation if the automation server is not available"
I use Kasa (TP-Link) plugs but there are a bunch of different brands.
My issue with those is that they fail the "normal person" test. A normal person will try to turn on a lamp and it will never work because the smart plug is off. But with a smart bulb, it'll come on after they twist the stem a couple times. (And it never gets noticed! People are used to 3-way style lamp sockets needing a couple clicks to turn regular bulbs on and off, so they don't really notice that they had to double twist the stem to get the light to turn on)
The best compromise are smart switches. Switch still manually controls the light, and smart features are always available. The downsides are that the lamp's outlet must have switch wiring, and smart switches aren't like normal toggles: they're more like push buttons so the switch isn't in a strange physical state.
(By the way, Philips Warm Glow bulbs are awesome for this. I use them in my dining room lamp connected to an Inovelli Z-wave dimmer. They get warmer the dimmer they go, mimicking how tungsten filaments work)
My current setup is a mix-n-match of all three types, using each one where it beats the other two for simplicity and predictability.
...immediately, every single time the occupant wants it to do that. Regardless of the state of any other component.