title: When to use ng-attr?
body: <p>It seems like using direct attributes and the <code>ng-attr-*</code> directive do the same thing. For example, the following render equivalently:</p>
  
  <pre><code>   &lt;div ng-attr-id="{{ 'object-' + value }}"&gt;ID&lt;/div&gt;
     &lt;div id="{{ 'object-' + value }}"&gt;ID&lt;/div&gt;
  </code></pre>
  
  <p>When should I use <code>ng-attr-*</code> and when should I use the direct HTML attribute?</p>