title: What is the point of using SubSink instead of a Subscriptions array
body: <p>I just watched a ngConf video of John Papa talking about SubSink as a best practice in order to unsubscribe from obversables.</p>
  
  <p>I was actually using Subscriptions[] then push subscriptions into it then forEach unsubscribe at cmp destroy.</p>
  
  <p>Is their something I missed or is it just a readability improvment to use SubSink ?</p>