No. They aren’t controlled via Internet (they can be, but it’s not vital). You have Zigbee switches that control them through radio. Or you control them with your Zigbee controller which is hooked up to your network, but works locally so even if your Internet is down it works on LAN.
voltage drops/brown outs/black outs … They all turn on the full brightness for “safety”
Depends on the brand. Some do this. Most do out of the box but you can go into the settings of your Zigbee controller and disable that. Some don’t let you configure it. I’d read reviews first.
No. They aren’t controlled via Internet (they can be, but it’s not vital). You have Zigbee switches that control them through radio. Or you control them with your Zigbee controller which is hooked up to your network, but works locally so even if your Internet is down it works on LAN.
Depends on the brand. Some do this. Most do out of the box but you can go into the settings of your Zigbee controller and disable that. Some don’t let you configure it. I’d read reviews first.
Also Phillips Hue is actually a Zigbee bulb, which can be used with non-Hue Zigbee controllers. If I’m reading right this setting can be configured. https://community.hueessentials.com/t/how-to-set-up-power-on-behaviour-for-my-lights/720