I know the risks about running php-fpm as root. However there are situations where one would need to do it, like appliances, accessing operating system resources or ev
See:
# php-fpm --help
...
-R, --allow-to-run-as-root
Allow pool to run as root (disabled by default)
Update 2018
Running it within a container is a possible valid reason to run php-fpm
as root. It can be done by passing the -R
command line argument to it
Original answer:
However there are situations where one would need to do it, like appliances, accessing operating system resources
You never need to do it. That's it. If you are managing system resources, grant permissions for the php-fpm user to that resources rather than running the whole process as root. If your question would be more specific I could show how to do that in a certain situation.