I also think "it shines in finance" is a little weird. It's used in finance because it's an industry with a premium on correctness and a sympathy for math, but I don't think it's generally better suited to solving those problems than to solving other problems. If I had to point to one area that Haskell is clearly better at than "mainstream" languages it would probably be tree manipulation - and as a consequence compilers - due to structural pattern matching (for small stuff) and evaluation strategies (for larger and more abstract stuff).