I've found that knowing categories to the extent that Haskell teaches them through osmosis is useful. For example, knowing functions are functors in the return type and cofunctors in the argument makes grasping co/contravariance in OO much easier.
I haven't found any utility to the CT that is above the scope of Haskell; it feels like if it's too advanced to implement in Haskell, it's too advanced to find a use case anywhere.
I haven't found any utility to the CT that is above the scope of Haskell; it feels like if it's too advanced to implement in Haskell, it's too advanced to find a use case anywhere.