QuickTime 3.0 Finder name suffix surprise

This may be in the QuickTime 3.0 documentation somewhere, but I have not yet spotted it: Take any editable SimpleText document. Add any one of the following suffixes to its name (the suffix should be preceded by a period): gif, jpg, mov, dif. You will find that the file's type, creator and icon change to match that of a GIF, JPEG, movie or digital video file respectively. Every time you change the suffix, the file will change accordingly. This feature apparently only works when QuickTime Settings' QuickTime Exchange option is enabled (an option that supposedly makes it easier to open files created on other platforms).

For files created on a Mac, I see no clear advantage to this feature. It does not actually change the content of the file of course. That is, even though the text file may now look like a GIF file on the desktop, it will not successfully open as a GIF image in an application. Still, it is kind of fun to watch the icon change. And it is one of the few cases I know where changing the name of a file in the Finder affects the nature of the file itself (StuffIt Deluxe's True Finder Integration can also do this). (Thanks also to Tracy Smith.)

Update: Brett Rann points out how this feature can be useful: When using PC files, "any file without a resource fork that has a 'media' extension will be given an appropriate icon and can be opened directly into the required application."