Well this has nothing to do with "Windows CommPort assignments." it is for finding the list of available ports with descriptive names and keeping it up to date if a USB adapter is plugged or unplugged in later.

The main use is probably for menus and pick lists, where the description could make it easier for a user to choose the correct port.

You might possibly use it for finding a port of a USB adapter if it "moves" (assuming it has a unique driver that gives it a unique description). This isn't completely reliable of course because you might have two or more with the same description at any given time.