What is the benefit of ember-restless?

Though I read the doc, I still do not know what benefit ember-restless provides. As it said in the doc, it simplifies Ajax calls and defining serializers. That is it? Just so you write less code to easily crud records by dealing with models and write zero Ajax code so you become restless? But isn't Ember model designed to have Ajax calls happen behind the scene?

So I thought that rest-less should be able to avoid writing any Ajax code, with modeling or other ways, take registration for example, but it seems not the case or I missed something. Confused. Why call restless?

Added: Is it that restless can replace ember data to skip the data store? Then I might see its greatness.