What are the advantages and disadvantages of using HTML entities like "ä" instead of direct character replacements like "ae" in PHP scripts?

Using HTML entities like "ä" instead of direct character replacements like "ae" in PHP scripts can ensure proper encoding and display of special characters, especially when dealing with different character sets or encoding issues. However, using HTML entities can make the code less readable and harder to maintain. It is recommended to use HTML entities when dealing with special characters that may cause encoding issues, but use direct character replacements for better code readability.

// Use HTML entity for special character
echo "ä"; // Output: ä

// Use direct character replacement for better readability
echo "ae"; // Output: ae