是否有理由在asp.net MVC上使用WCF？

If I am using knockout.js or angular.js for the presentation layer, also assume that the service layer needs to write data and read data from the database and it holds the business rules. Is there a reason why I should use WCF over asp.net MVC for the service layer? Calling an MVC controller that returns JSON data seems pretty simple, I can't think of a reason to use WCF.If I am using knockout.js or angular.js for the