What are the potential pitfalls of converting time values to UNIX timestamps in PHP when working with database scripts?

Converting time values to UNIX timestamps in PHP when working with database scripts can lead to potential pitfalls such as time zone discrepancies and loss of precision for milliseconds. To solve this issue, it's recommended to store time values in the database as datetime or timestamp data types instead of UNIX timestamps.

// Storing time values in the database as datetime data type
$datetime = date('Y-m-d H:i:s');
$query = "INSERT INTO table_name (datetime_column) VALUES ('$datetime')";
mysqli_query($connection, $query);