With a lower noise level for drying there is less disruption and you could use the dryer at night.
With a delay start option you can schedule the machine to begin at a later time. You can also set the machine to wash at night if your electricity is cheaper outside of peak times.
More weight capacity helps if you want to wash something heavy like curtains. A traditional household machine can hold around 6kg, so with a machine much bigger you may waste energy using it when only half full.
Machines with auto finish will switch off automatically when the laundry is dry. This will prevent overdrying and save on running costs.
The machine will analyse how much heat is needed in order to dry each specific load, therefore increasing efficiency and saving energy.
Condenser dryers extract the water from the damp air in the dryer and store it in a container. They are good because they can be put anywhere in the home whereas vented dryers should be next to an outside wall.