Yeah, 5-spice powder is usually dominated by cinnamon. I've been using cinnamon (along with szechuan peppercorn and toasted cumin) to make the garlic chili oil for biang noodles at home. Similar to how it helps in a garam masala, it adds a lot of depth when it's mixed with a vinegar and soy sauce. It's really an amazing depth that it adds. It also plays a part in making hoisin sauce.