No one uses Haskell, or no one uses those optimisations?

Haskell has plenty of industrial users and quite a few very large programs as well. Those libraries hardly look mature - I know that many of the container libraries on Haskell make extensive use of unpacking, for instance.

Here is a good set of slides on Haskell and optimisation: http://www.slideshare.net/tibbe/highperformance-haskell