Comment by zogrodea

I can't speak for others, but I never really understood the benefits of functional programming when my language pretty much allowed unbounded mutation anywhere. I would say there's a chance for impure languages to impede you in learning what functional programming is about (or at least my experience with F# and OCaml did not really help as much as it otherwise could have I think).

Your mileage might vary, but I've heard advice from others to learn Haskell and "go off the deep-end" because of people citing similar reasons.