title: What is the purpose of $eq
body: <p>I noticed a new <code>$eq</code> operator released with <code>MongoDB 3.0</code> and I don't understand the purpose of it. For instance these two queries are exactly the same:</p>
  
  <pre><code>db.users.find({age:21})
  </code></pre>
  
  <p>and </p>
  
  <pre><code>db.users.find({age:{$eq:21}})
  </code></pre>
  
  <p>Does anyone know why this was necessary?</p>