In reply to Marcus.

As for whether it's important for regular users, it really depends. You wouldn't want to go into the site editor and remove the Query block from the category template, for example. Your posts would not show on category archives on the front end in that case. That low-level of understanding is probably necessary for users who are tinkering in the site editor.

For deeper customization, it will be a powerful tool. You might want to create a custom front page that lists specific posts. Maybe even do a magazine/news front page with multiple sections of posts from different categories.