Energy display devices that come with a Smart Meter are known as Customer Display Units and allow you to see where you use the most energy, which can help you to reduce your energy consumption and also your carbon emissions.
Your display unit can play a part of your fight against climate change, as well as helping you make energy-reducing decisions that could also help you save money.
Energy display devices that don't come with a Smart Meter, measure only the current flowing through the cables they are attached to (Smart Meters measure both current and voltage), so it can be less accurate than a smart meter.
They 'stand alone' and do not communicate with your supplier, which means that your bill will not necessarily be based on the same readings shown on the display device.