Finding "F# jobs" is a lot easier in my experience, due to easy interop with C#. Many places using .Net or C# are willing to let you use F# in places if you can convince them it makes sense.

As to the question of it being "worth it". I learnt more about becoming a better programmer by learning Haskell than probably any other single thing I've done. And while I've never written Haskell professionally and haven't used Haskell in probably a decade, I use many of the concepts and principles I discovered via Haskell almost every day.