It's not really a "Why you should use Perl instead of X" either.
It seems more like, "Perl's Not Dead, It's Just Schizophrenic Now". It attacks the idea of "Perl is Dead" with a description of the rather confusing state of "modern Perl". It doesn't exactly make the ecosystem sound all that enticing, not here in 2013 when there are so many other viable options.
I think the "Why I love Perl" part is pointed out by the community and that Perl 5 basically spawned Perl 6, which is a different programming language.
I pretty much agree that Perl 5's popularity is really low, despite lots of great minds and exciting approaches. I switched to Node.js, CoffeeScript, Go, etc., but it is like everything I do could have been better or equally done in Perl and the tools were more mature. It's the same with all the new concepts and always makes me think about the MVC hype, when the concept of MVC was first named in the 70ies. It's a bit like with Smalltalk. It took like 30 years until people ralizing how good it is and reinventing it.
Same with "Do things the Unix way", pipes, KISS, NoSQL, distributed systems, all the stuff that the EC2 made popular. In that sense Computer Science is a really slowly developing science. At least it appears like that, maybe others are similar. I don't know.
And what is happening right now for example is making Javascript C, while the developers of C are stepping towards dynamic languages (Go). Also functional progrogramming laguages reappear, first Haskell, now Clojure reapear, cause it is cool for async stuff. LISP has been around for ages and Scheme is really beautiful and neither of them was ever slow or anything. Just look at Racket. It's pretty powerful, amazing to learn, performs at least okay and its IDE is pretty nice and cross-platform. It's amazing for doing the same stuff as Node.js and Scheme is one of the easiest languages to implement.
But back to Perl. It has a lot of problems. Nobody ever talks about how awesome CPAN and CPAN-Testers is (you don't even need to set up Travis CI). Nobody ever talks about it as functional programming language, even though there is a great book about. Another problem is that it is way more optimized for getting actual problems done and doesn't really perform too well, when you show your average snippet that looks mostly the same in every programming language out there.
The last flaw is that Perl is probably the hardest programming language to learn, because there are so many bad books out there. There are books like Modern Perl, that even are free, but also many really bad ones.
And a lot don't tell you about use strict; use warnings; use diagnostics; right away, even when they are what every beginner wants.
They even have a page dedicated to sifting through tutorials and guides, and assessing their usefulness for learning Modern Perl - http://perl-tutorial.org/learn/
When CPAN dies, perl dies. Is CPAN still my best hope for "easy interface to something really weird but very important"? Oh it is? Well then Perl it will be.
I find it extremely hard to justify on the job writing and debugging something that "just works" off a 30 second install from CPAN.
Note this criteria doesn't matter much for boring CRUD webapp number 246264. There are somewhat more optimized solutions for that very small subset of problems.
These are the guys who if you Google their email address, it will show one or two posts to usenet between 1995 and 2013 and nothing else. No Twitter account, no Facebook profile, no prolific profile on Reddit or HN. Just silent work and go home.
Or maybe that's the wrong way to look at it.