Update README [ci skip]

Author: n-rodriguez

README.md

@@ -438,6 +438,9 @@ end
 If you want to keep things tidy in the data mapping method, you could use
 [Draper](https://github.com/drapergem/draper) to define column mappings like below.
 
+**Note :** This is the recommanded way as you don't need to inject the `view_context` in the Datatable object to access helpers methods.
+It also helps in separating view/presentation logic from filtering logic (the only one that really matters in a datatable class).
+
 Example :
 
 ```ruby
@@ -483,8 +486,6 @@ class UserDecorator < ApplicationDecorator
 end
 ```
 
-This way you don't need to inject the `view_context` in the Datatable object to access helpers methods.
-
 ### Pass options to the datatable class
 
 An `AjaxDatatablesRails::ActiveRecord` inherited class can accept an options hash at initialization. This provides room for flexibility when required.