title: Rx.Observable.fromEvent(document, 'click') Vs. document.addEventListener('click', callback)
body: <p>I just start learning reactive programming &amp; using RxJS library.</p>
  
  <p>One thing that is making my head turning is why would i use Rx while there the notion of events in JavaScript.</p>
  
  <p>For example, What is the diff between <code>Rx.Observable.fromEvent(document, 'click')</code> and <code>document.addEventListener('click', callback)</code>. Both are handling <code>click</code> events asynchronously.</p>
  
  <p>So why would I use observables in this case?</p>