With a bigger drum you can fit in larger items such as duvets, or do a big load at once.
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.
A two way tumbler spins in two directions. This is good for efficient drying and for untangling the load.
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.
Vented dryers are cheaper and can be more efficient than condenser dryers. The damp air extracted travels through a long plastic hose and is discharged outside the home, either through a window or hole in the wall. You don't have to empty a water container like you do with some condenser dryers.