I love remote files. For web development, this kind of feature is exceptionally useful.
Need to work with the contents of a web page? A simple
$fp = fopen('http://example.com');
and you've got a file handle ready to go, just like any other normal file.
Or how about reading a remote file or web page directly in to a string?
$str = file_get_contents('http://example.com/file');
The usefulness of this particular method is hard to overstate.
Want to analyze a remote image? How about doing it via FTP?
$imageInfo = getimagesize('ftp://user:password@ftp.example.com/image/name.jpg');
Almost any PHP function that works with files can work with a remote file. You can even include() or require() code files remotely this way.