stelfox just asked about a manual switch that turns it off if it's on, on if it's off.
The problem is the latter part of your statement, "on if it's off".
A smart bulb won't reliably do this - if the bulb has power but is in the "dark" state by its IoT controller, flicking the switch will remove power and have no effective impact on the state of the bulb.
if the bulb has power but is in the "dark" state by its IoT controller, flicking the switch will remove power and have no effective impact on the state of the bulb.
The problem is the latter part of your statement, "on if it's off".
A smart bulb won't reliably do this - if the bulb has power but is in the "dark" state by its IoT controller, flicking the switch will remove power and have no effective impact on the state of the bulb.