Outlook offers so much more than just sending and receiving emails.  Used correctly you can manage your diary ensuring you never miss another appointment.  You can keep track of your to-do list and, if lucky, delegate some of your tasks to others whilst monitoring progress through the system.  You can even keep track of emails sent to and received from individual contacts through their contact record.

If your calendars are shared, you can use Outlook to check colleagues' availability for meetings, send a meeting request and keep track of their responses.