It offers over 30 free starter-site templates and a one-click demo importer to get you started quickly. Customization is easy thanks to its compatibility with the Elementor page builder plugin. For more advanced design options, it allows adding custom CSS.
Free WordPress themes are indeed totally free, with no strings attached. The lack of features in free themes makes them lean, and therefore typically faster to load. Premium themes will come with far more functionality out of the box. Ongoing support and updates mean premium themes are more secure in the long run.