Haskell is cute until somebody in the team starts using the most advanced parts in some common task, destroying team's ability to understand what's going on and

Haskell is cute until somebody in the team starts using the most advanced parts in some common task, destroying team's ability to understand what's going on and make changes; in a few years the author of such code will have the same problem (one's brain won't keep PhD-level capabilities the whole life). The same issue hit Scala development and led to complete rewrites back to Java or similar.