By default, WiZ lights turn on when they are powered on. Depending on the power switch options you have selected, they will either adopt one of their favorite modes or their previous light status before they were powered off.
This can occasionally create disturbances if your home is subject to power outages or brown outs, especially during the night. You may not want your lights to turn back on and wake you up.
Or if you have a holiday home, you may want to make sure your lights stay off when you are away.
In the settings of your home, you can enable Power outage recovery.
When this option is active, lights which get powered off while they were turned off, in night light or in bedtime mode will not turn back on when the power comes back.
If you need to turn them back on with the power switch, power on quickly twice in a row.