Outlook/Exchange 2007 AutoDiscovery?

One amazing new feature that Microsoft's Outlook 2007 has implemented is called "AutoDiscovery". Basically, this feature can automatically fill out your email server information for you, based on your email address. What a neat feature! What isn't neat about it, is how Microsoft has implemented the feature though…

As published here

Microsoft has decided to create their own standard for automatically configuring email clients. To sum up their docs, Outlook 2007 looks for a specially formated XML file sitting on a web server, and if that fails, Outlook 2007 tries logging into yourdomain.com, mail.yourdomain.com, pop3.yourdomain.com, etc.

So what's wrong with using an XML file sitting on a web server for client auto-config? Simple! A STANDARD already exists!! It's called DNS SRV records.

Without spending too much time reiterating what the wikipedia article already tells us, DNS SRV records give us a fantastic method for client automatic configuration. Your email client queries your DNS server with "hey whats the server address for pop3?" and your DNS server replies back "oh the pop3 server is called cats123.yourdomain.com"

So why the need for this "AutoDiscovery" service? Anyone know a good reason why a specially formated XML on a web server must be used in place of DNS SRV records??