title: What is a real-world example of block scope being useful in JavaScript?
body: <p><code>let</code> and <code>const</code> have introduced block-level scoping to JavaScript, and I now understand the difference. But I'm yet to find a compelling real-world example where <code>let</code> has an advantage over <code>var</code>.</p>
  
  <p>What does block-scoping offer in practical terms (illustrated by example)?</p>