A chminey is used to ignite charcoal. In my opinion, they are very useful, because they are very easy and save in usage, ignite charcoal quick and ensure an uniform and equally heating of the coal.
You simply put the charcoal into the chimney and place some lightened papers below it.
Afterwards you can grab a beer, chat with your guests and after about 10 minutes, your charcoal is ready.
Flip over the chimney, arrange the charcoal and put on the meat ;)
Pros of the chimney:
-Easy and save in use
-No chemistry
-No additional smoke
Cons of the chimney:
-Takes some time
-You need a chimney