@AMBxx - Re: Still around?
Two reasons for you:
1. Ability to force displaying of emails in plain text (i.e. no script execution and no remote content)
2. Ability to display a message in its source form without opening it so you can see all the nasties in it without actually running them.
No other email client standalone or (especially) web based offer these abilities which in my opinion are an invaluable security tool.