The left panel is a four-level class hierarchy. UserProfilePage extends DataLoader extends AuthComponent extends BaseComponent. When render() is called on UserProfilePage, it calls super().render() which bounces up to DataLoader, which calls super().render() which bounces up to AuthComponent, which calls super().render() which bounces up to BaseComponent. BaseComponent finally does its work and returns. Control flows back down through each level. The call stack goes down, up, down, up, down, up, down. Seven direction changes. Four super() calls. To understand what UserProfilePage.render() actually does, you must read four files and trace the execution through all of them.
The right panel is a flat pipeline. The request passes through authenticate, then validate, then load_user, then render_profile. Each function receives data and returns data. Control flows in one direction: forward. Zero direction changes. Zero super() calls. To understand what happens, you read the pipeline top to bottom.