Sometimes you need to remote control an AC outlet that powers something (like a heater or a light or motor etc). There are different IoT solutions out there like the PowerSwitch Tail which allows hooking up your arduino/IoT device of choice and control 1 outlet.
Naturally, having created the SwitchMote kit, and after being asked in the forums if this could be modded/used to control AC outlets, I made a quick video of how to implement an AC outlet switch-box using a SwitchMote 2x10A, allowing control of 2 independent outlets with local button control as well as visual feedback via the status LEDs of the SwitchMote.