Choosing a language for a project rarely comes down to researching the languages that may best deal with the problem. More often than not from my experience, it’s what the first engineer(s) on the project thought would be fun (annoyingly often in the case of using new languages in production), were most-familiar in, or the company is most familiar with, or because some library they need to use is only available in X language and it would take too long to do the project and implement the library in their “normal” language.

Perl, Python, and Ruby are all pretty competent and on the same level. Given that Perl is chosen as a language the question isn’t “Justify the use of Perl to the exclusion of Python and Ruby.” It’s “What can Python or Ruby do that Perl can’t?”

Some common arguments between Python and Perl can be found at http://coosoft.wordpress.com/2013/02/24/the-perl-vs-python-d... (I would add the author should have expanded on Object Oriented in Perl more. While native OO in Perl is exceptionally basic, third party OO frameworks for the language exist such as Moose and Moo complete with introspection, roles, type constraint, triggers, attributes, etc, etc).

Perl is a powerful modern language, actively developed by a committed community[1]. We’re just generally too busy doing things to blog about all the awesome stuff as much, so people’s perceptions of the language are often stuck in 1998.

[1] https://www.youtube.com/watch?feature=player_detailpage&v=hH...