Over time I’ve seen, and read, and presented quite a lot of motivations for the use of purely functional programming — sometimes for Haskell, Lisp, or ML. Today I’ve seen the first motivation/introduction which did not come from a mathematical/categorical perspective. That was quite refreshing. You can find it here.
Although, there is nothing really new in it — at least not for someone who has been following Haskell for 10 years now — this is a nicely presented new angle on the topic. So, have a look at that talk and see for yourself.