The reason why you put dark chocolate in chili con carne is to create a richer and deeper and more complex flavor.
Adding dark chocolate to chili con carne enhances the umami of the meat and spices, without adding a noticeable chocolate taste.
The chocolate enhances the umami and creates a richer and deeper and more complex flavor of the chili con carne by balancing the acidity of tomatoes and mellowing of the spices, which is similar to how chocolate is also used in mole sauce, which results in a smoother and more intense, savory dish.
The difference between chili and chili con carne is chili is a broader term that can be a meat based dish but also can include meatless variations in ingredients such as vegan versions and vegetarian versions.
Chili con carne is a more specific term that implies a dish that is focused on meat and chili peppers, and chili can encompass other dishes with beans, corn and other vegetables alongside of or instead of meat.
The words chili con carne in Spanish means "chili with meat".
The key ingredient in chili con carne always contains meat, often ground beef, beef or any other meats.
And chili con carne is rooted in Mexican and Texan cuisine, with traditional chili con carne recipes emphasizing on meat and chili peppers.
Other ingredients in chili con carne can also include chili powder, garlic, onions and some chili con carne recipes also feature tomatoes.
Chili is a more general term for the chili dish and can be either meatless or meat based.
Common ingredients in regular chili can include beans and other vegetables as well as different spices, depending on personal preference and regional style.
In modern usage, "chili", is also often used to describe any variation of the chili dish, and not just meat based chili dishes.
Chili con carne, is basically a spicy stew of Mexican origin, that contains chili peppers, meat, tomatoes, pinto beans or kidney beans and other seasonings like cumin, onions and garlic.