It replaces the nicotine that you would have gotten from cigarettes with a cleaner form of nicotine (minus all the other chemicals found in cigarettes)
For example, a study of internal tobacco industry documents found that smokeless tobacco product manufacturers added flavors to their products to attract new users, especially young males
That enabled the Cigarette design crew to maximize cockpit space aft of the second row of shock-mitigating, multi-position bolsters
In culture [edit] Arthur Conan Doyle paid a casual tribute to the popularity of Egyptian cigarettes in his 1904 story "The Adventure of the Golden Pince-Nez", where a character interviewed by Sherlock Holmes in a murder investigation is described as a very heavy consumer of them
(Also, did you catch Mel from "Flight of the Conchords" as one of the switchboard operators
Cattlemen even used mullein to treat cows, hence its nickname Bullocks Lungwort