Hi
well outlook on your PC means you can read email whilst not connected to the internet, as the emails are stored either on the local PC or in a corporate layout on a network drive.
Its easier to sort out as the mail is on the PC, rather than on a remote server, we all know the internet is slow at times and remote servers can fail leaving you without the ability to read emails.
also outlook in companies send/receives internal mail as well as external mail.
Companies can impose restrictions on what type of mail is sent/recieved, this includes blocking malicious programs such as exe file etc and prevents the spread of viri.
Outlook has a much better interface which includes several things like reminders, calenders, journals etc.
I also find mail sent direct to my inbox gets there quicker than mail sent to my Hotmail account.
Just my thoughts