What are the implications of using echo versus include for displaying text in PHP, especially in terms of SEO and performance?

Using `echo` to display text in PHP is more efficient in terms of performance compared to using `include`, as `include` is used to include and execute files. However, when it comes to SEO, using `include` to display text might be more beneficial as search engines can crawl the content within the included file. To balance performance and SEO considerations, you can use `echo` for simple text display and `include` for more complex content.

<?php
// Using echo for simple text display
echo "Simple text content";
?>

<?php
// Using include for more complex content
include "complex_content.php";
?>