Cinnamon is mostly used ground, although I have a few recipes that use the whole cinnamon stick. Whole cinnamon is used often in asian cooking, and the one recipe I make in that cuisine is Pho soup, and it uses whole stick cinnamon for flavor. I also make a beef stew using stick cinnamon for flavor.
In both of those recipes, I remove the cinnamon before serving. It's there for taste not the eating