Having popular interfaces like monad, applicative functors, monoids etc also suggests common ways to structure any API you are working on.
If you design an API from scratch and have to implement everything again and again, you might be tempted into a pretty arbitrary breakdown of the problem space.
Whereas in Haskell personal laziness drives you to look hard to see if you can express your API in terms of foldable and traversable or monads etc so that you get lots of functions for free.
Those common interfaces also automatically suggest gaps in your API that otherwise you would have only noticed after using your API for a while (or by being a very experienced programmer).
Having popular interfaces like monad, applicative functors, monoids etc also suggests common ways to structure any API you are working on.
If you design an API from scratch and have to implement everything again and again, you might be tempted into a pretty arbitrary breakdown of the problem space.
Whereas in Haskell personal laziness drives you to look hard to see if you can express your API in terms of foldable and traversable or monads etc so that you get lots of functions for free.
Those common interfaces also automatically suggest gaps in your API that otherwise you would have only noticed after using your API for a while (or by being a very experienced programmer).