Why put cinnamon in chili? We had an office chili cook-off recently (I didn't enter). Two of the chili recipes presented used cinnamon predominately, perhaps even overpoweringly (IMO). Given that they also heavily sweetened their chili with honey and sugar, both had a cinnamon dessert flavor profile mixed with a bland tomato/beef profile. In a word, "yuck!"

In searching today, I've seen several recipes around calling for the use of cinnamon in chili. I could see it maybe being a background flavoring to add a mild spicy bite and a touch of earthiness. But, some recipes seem to be pretty heavy in it's use.

I'm assuming the office cooks didn't develop the right flavor (unless going for a dessert chili was their objective). What kind of flavor profile would be the right one to develop when using cinnamon in chili?
Cinnamon adds a different spice profile than chili powder or red or cayenne pepper would. It is a common savory spice in Indian food and I believe it's also used in savory dishes in Chinese cooking. It's a very versatile spice :).

We also use cocoa powder in our chili as it provides a real depth of flavor (dark bitter flavors which are quite good in chili). 

Both of these add some curiosity and difference to the chili without themselves adding sweetness. Usually they get added as a fairly safe way to add something "different" to standard chili.