The reasons for this are legion. I can't count how many times I have accidentally hacked a profile only to discover I went after the wrong one. If I didn't put the profile down in my notes I have to guess to get it back. If they are in a folder then they could be archived. Not only that, users should share profiles, which you cannot easily do when they are dumped as an XML file or in a registry. Unless, of course, you like bunches of typing and mouse clicks...
Thanks,
DLC