Inert files are unrealistic, normally you use PHP server to execute PHP code, which this website doesn't appear to do (only static files). And suppose you want to accept >1mb file uploads, that limit would get in your way. So it's not a good representation of a PHP application, but for other uses it's reasonable.
So why did the original warning put out by the PHP team say that the exploit didn't rely on the application code and simply having software like Apache mod_php running would be enough?
https://www.php.net/archive/2026.php#2026-10-21-5