When you work in WordPress development for a while, you get used to seeing path handling like
ABSPATH . 'wp-content/plugins/plugin/plugin-name.php';
Such code is… let’s go with fragile. It relies on a common WordPress directory structure, the one it can easily be configured out of.
Whenever you work with paths you need to be aware of both directory structure and how it can be configured. You need that to write reliable code to handle paths.