I don't expect to ever write Haskell in production. Oh, sure, some places do, but they're very, very few; I suspect it's pretty much impossible in any area where you expect to grow, simply because finding people who know it already is nearly impossible, and learning it is difficult, especially as your established crew learns new and more powerful abstractions; the amount of learning required to get someone up to speed gets higher and higher, which is not what you want as you expand.
But that said, as a developer even in more approachable languages, learning that cleverness has its benefits. It provides new insights into ways problems can be expressed. Most developers agree on the benefits of learning a new language; you learn a few good ideas, a few paradigms and approaches, that can carry over and affect the way you code in your day to day. Haskell, with its depth, is better still; you have a seemingly neverending set of ideas to learn and draw from. Many, yes, are too clever to see a full implementation elsewhere in production code that has many maintainers. But borrowing even part of an idea expressed in Haskell may lead to a simple, reusable, and concise solution to a problem that otherwise would be an ugly bug riddled one off solution.