CP Update without extending Ember Object

controllers.application.js

import Controller from '@ember/controller';
import { computed, set } from '@ember/object';

export default Controller.extend({
  appName: 'Ember Twiddle',
  
  actions: {
    updateThingName() {
      set(this.thing, 'name', 'C');
    }
  },
  
  greeting: computed('thing.name', {
    get() {
    	return `Welcome ${this.thing.name}`;
    }
  }),
  
  init() {
    this._super(...arguments);
    this.set('thing', {
      name: 'A',
      greeting: computed('name', {
        get() {
          return `Hello ${this.name}`;
        }
      })
    });
  }
});

templates.application.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}

{{greeting}}

{{thing.greeting}}

<button onclick={{action 'updateThingName'}}>
	Update a thing name
</button>
<br>
<br>

twiddle.json

{
  "version": "0.15.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.2.2",
    "ember-template-compiler": "3.2.2",
    "ember-testing": "3.2.2"
  },
  "addons": {
    "ember-data": "3.2.0"
  }
}