It is tempting to say that Haskell is the same for hardcore Math nerds as perl was for hardcore UNIX nerds (better than shell with better regexps), but it doesn't stand.
It seems like this is rather cultural phenomena, about being able to say or show off something cool and clever, something special, not for everyone.
There are no shortage in analogies. Yoga and Oriental philosophy in general - everyone starts to talk unimaginable nonsense using words "chakra", "dharma", "atman", "brahman", etc. Sounds very distinguished.
Few decades before everyone used to insert at random places words "unconscious", "repressed", "libido", "alter-ego", then, "stimulus", "reinforcement", "conditioning"..
Now it is fashionable to talk about functional programming, the same way it was fashionable to talk about object-oriented one in 90s. New pop-culture.
But it will not work unless you have the aura of being sophisticated. All those references to advanced branches of mathematics and fancy theories creates an illusion of touch with real science - the same way they put block diagrams and on a tooth-cream.
So, if some young guy managed to express some idea using this special sophisticated, incomprehensible by mere mortals syntax, he wrote a long blog post, praising his own cleverness.
Now some bloggers argue that one should place Haskell as a must-have requirement for a job applicant, because, you see, they must be really smart if they can code in it.
Just imagine what a disaster could be a project where each coder will try to show how clever he is. The same phenomena - look how clever I am - have been seen in Perl and C++ worlds. Unreadable spaghetti, which even author can't read two weeks later.
It is also possible, that I'm just isn't sharp enough to "get it", to appreciate esoteric qualities, which makes this language superior to Erlang or Lisp, which I really admire and love.
It that case it is a Perl for Mach nerds, which means a disaster for rest of us.