Smart outlets are outlets that simplify device automation by connecting to Bluetooth or Wi-Fi networks. They work by being plugged into an outlet and connecting to the Wi-Fi network. Once the outlet is connected, you can plug in a wired device and control the device whenever you need to from a phone or remote.
Yes, smart outlets save energy. Most smart outlets use around 1 to 2 watts of energy which means they do not need much energy to work. The needed energy is from electricity that is used for Wi-Fi purposes.