What are the potential pitfalls of using regular expressions for validating HEX content in PHP?

Using regular expressions for validating HEX content in PHP can be error-prone and may not cover all edge cases. It is better to use built-in functions like `hex2bin` and `bin2hex` to convert the HEX string and validate it.

function isValidHex($hexString) {
    $binaryData = hex2bin($hexString);
    if ($binaryData === false) {
        return false;
    }
    return true;
}

// Example usage
$hexString = "1a2b3c";
if (isValidHex($hexString)) {
    echo "Valid HEX content";
} else {
    echo "Invalid HEX content";
}