Closes #660

Author: sobolevn

docs/pages/pipeline.rst

@@ -1,3 +1,5 @@
+.. _pipelines:
+
 Pipelines
 =========
 

docs/pages/quickstart.rst

@@ -13,6 +13,39 @@ which will unravel all parts of functional programming
 with useful examples and simple terms.
 
 
+Why
+---
+
+One of the most frequent questions
+Python developers ask: why would we need this?
+
+Basically, the answer is that ``return`` provides
+useful abstractions that solve some problems every developer has:
+
+1. :class:`~returns.maybe.Maybe` helps to work with ``None`` in a type-safe way
+2. :class:`~returns.result.Result` helps
+   to work with exceptions in a type-safe way
+3. :class:`~returns.io.IO` helps to separate pure code
+   from impure code to make your architecture better
+4. :class:`~returns.future.Future` helps to write ``await`` free code
+5. :class:`~returns.context.requires_context.RequiresContext` helps
+   to inject dependencies in a very readable, explicit, type-safe, and clean way
+6. :ref:`pipelines` can be used independently or together with the types above
+   to create complex, declrative, and type-safe data pipelines
+
+On top of that we provide useful interfaces that allows you
+to switch implementation on the fly.
+For example, you can write code that works the same way
+for sync and async execution flows.
+While being fully type-safe at the same time.
+
+And you can write your own primitives that will solve any other problem
+you can possible have based on our existing or your custom interfaces.
+
+In other words, ``returns`` unlocks insane powers
+of typed-functional programming to a regular Python developer.
+
+
 Installation
 ------------