Add benefits of abstraction to documentation

docs/contracts.rst

@@ -1078,8 +1078,6 @@ Such contracts cannot be compiled (even if they contain implemented functions al
         function utterance() public returns (bytes32) { return "miaow"; }
     }
 
-If a contract inherits from an abstract contract and does not implement all non-implemented functions by overriding, it will itself be abstract. 
-
 Note that a function without implementation is different from a :ref:`Function Type <function_types>` even though their syntax looks very similar.
 
 Example of function without implementation (a function declaration)::
@@ -1090,6 +1088,9 @@ Example of a Function Type (a variable declaration, where the variable is of typ
 
     function(address) external returns (address) foo;
 
+Abstract contracts allow you to decouple contract definition from implementation providing better extensibility and self-documentation and 
+facilitating patterns like `Template method <https://en.wikipedia.org/wiki/Template_method_pattern>`_ and removing code duplication.
+If a contract inherits from an abstract contract and does not implement all non-implemented functions by overriding, it will itself be abstract.
 
 .. index:: ! contract;interface, ! interface contract