php：有没有理由在回显数据之前先填充结果数组

I'm reading sitepoint's book PHP & MySQL Novice to Ninja and I'm wondering why he takes an extra step.

My SQL query is

try
{
    $sql = 'SELECT * FROM trazooevents WHERE county = :county';
    $s = $pdo->prepare($sql);
    $s->bindValue(':county', $_POST['search_term']);
    $s->execute();

    include 'events.inc.php';
}

and in my include

<?php foreach ($s as $row): ?>
    <li class="db-headline"><?php echo htmlspecialchars($row['eventname'], ENT_QUOTES, 'UTF-8'); ?></li>
    // etc.
<?php endforeach; ?>

and it works perfectly fine. In the book Kevin Yank adds an extra step similar to:

foreach ($result as $row)
{
    $events[] = array(
    'eventname' => $row['eventname'],
    'eventdetails' => $row['eventdetails'],
    'weburl' => $row['weburl'],
    'imagename' => $row['imagename'],
    'expireson' => $row['expireson']
    );
}

Does he do this to just get an index label or is there some security issue I don't know?

It's a matter of readability of the code. You won't use row but an array with more semantic significance: events.

It is just to get the index label.. not necessary though.. :)