Content and Title filters, shortcodes

I have this shortcode:

// Highlighting shortcode
function caption_shortcode($atts, $content = null){
	return '<span class="highlight">'.$content.'</span>';
}
add_shortcode('h', 'caption_shortcode');

And printing my content using:

$content = $post->post_content;
$content = apply_filters('the_content', $content);
$content = str_replace(']]>', ']]>', $content);
echo $content;

This is working great =)

However, this code is kinda copy pasted, and im curious about what exactly its doing. From experimenting I learned that without the apply_filters() function, my shortcodes did not work. But the str_replace() function didn’t seem to make any difference on my theme.

Also, I wanted to use shortcodes in my title, so I did the same thing to it as with the content:

$title = $post->post_title;
$title = apply_filters('the_content', $title);
$title = str_replace(']]>', ']]>', $title);
echo $title;

Is it wrong of me to use a the_content filter on the title?
And still, is the str_replace() necessary?
Is there a better way to do this?