What are the potential pitfalls of using unnecessary variables in PHP scripts, as seen in the provided code snippet?

Using unnecessary variables in PHP scripts can lead to code clutter and confusion for other developers trying to understand the code. It can also impact performance by consuming unnecessary memory and processing power. To solve this issue, unnecessary variables should be removed from the code to improve readability and efficiency.

// Unnecessary variables in PHP script
$number = 10;
$doubleNumber = $number * 2;

// Code snippet without unnecessary variables
$number = 10;
$doubleNumber = $number * 2;