To convince managers I believe you should emphasize at the language’s practical potential.

Nowadays there’s nothing as important as software scalability, and you have a beautiful story to tell: the scalable and composable concurrency using the Software Transactional Memory model, the semi-implicit and explicit parallelism, the distributed systems programming (e.g., clusters) using Cloud Haskell. There also are thousands of open-source libraries in the every growing central repo. The community is eager to help.

There are lots of video presentations covering the topics I mention. I recommend walking thru the ones by Simon Peyton Jones for a start.