ember initiaizers vs service

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
   appName: 'Ember Twiddle',
    welcome: Ember.inject.service('welcome-service'),
  init(){
    console.log(this.get('welcome').name, this.get('foo').name);   
  }
});

initializers.my-service.js

export function initialize(application) {
  application.inject('controller', 'foo', 'service:my-service');
}

export default {
  name: 'foo',
  initialize: initialize
};

services.my-service.js

import Ember from 'ember';

export default Ember.Service.extend({
  name: "Saravanan"
});

services.welcome-service.js

import Ember from 'ember';

export default Ember.Service.extend({
  name: "Hello world"
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>
{{foo.name}}

twiddle.json

{
  "version": "0.13.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.16.2",
    "ember-template-compiler": "2.16.2",
    "ember-testing": "2.16.2"
  },
  "addons": {
    "ember-data": "2.16.3"
  }
}