title: When map over a function is useful when you have andThen
body: <p>With Scalaz, a function can be mapped over another function. When would I want to use <code>map</code> over <code>andThen</code>? Is there a clear advantage using <code>map</code>? Thanks</p>
  
  <p>For example,</p>
  
  <pre><code>val f: Int =&gt; Int = (a) =&gt; a + 10
  
  val g: Int =&gt; Int = (a) =&gt; a * 100
  
  (f map g map {_*3})(10) == (f andThen g andThen {_*3})(10)  // true
  </code></pre>