All languages are different. There are no better languages to code in. Languages have strengths and weaknesses.
The clear choice to use perl or php to backend a site, is the coder.

I went from mainly php to perl 5 years ago.
The vast majority of my work in perl has nothing to do with the web. But when so, I use CGI::Application.

If you choose perl to develop some web trinket- and must present a case. Learn CGI::Application. Take a seat on your workstation and put a php coder in another. See who can code this faster:
Allow use login, allow file upload, allow searching for files.

That will be the end of discussion.

However, this is unjust. Possibly cruel.