Have you ever wondered what the difference is between get_template_directory_uri and get_stylesheet_directory_uri? The Codex starts off by telling us that they return the template directory and stylesheet directory of the current theme. This turns out to be exactly the same, if you are only using a parent theme.

If you are using a child theme these functions will return different results.

//Returns the parent directory.
get_template_directory_uri();

//Returns the child directory.
get_stylesheet_directory_uri();

This begins to make sense when you recall that Child themes override the parent theme CSS, so it seems right that your stylesheet directory is in the child theme. While you are still probably using most of the functionality from the parent theme so this remains your template directory.

Most child themes will simply add or overwrite a few actions or filters in functions.php and almost always override styles in style.css.