dynamic looping on a controller property

I am using ember 2.17.

I added this property to a controller :

export default Controller.extend({
  newAttachments: new Array()
...

I add elements in it through this controller action :

setAttachment(file){
      console.log('trying')
      this.get('newAttachments').push(file)
    }

When I us the action, the message is displayed in the console, and in Ember inspector I can see the array is no longer empty :

However, the following code in the view has no output :

  <p>in loop</p>

Why is it not displaying anything? In a component it would work, why not here ?