What is the purpose of pressurizing an airline cabin?

The purpose of pressurizing an airline cabin is to provide a comfortable flight for the passengers and aircrew. Cabin is also pressurized so that the aircraft structure will not be damaged due to differential pressure. If the cabin pressure is below 10p.s.i. the passengers and aircrew will not be able to breathe and anorexia starts to occur which can lead to drowsiness and fatality. Therefore cabin pressurisation is very important.