there really are no benefits to smoking other than the quick drug-delivery system. Nicotine, however, has a lot of valuable effects. They just need to work on the delivery system.
Well, regular smokers certainly report that. But what it really reduces is the stress associated with a shortage of nicotine for those habituated to regular doses of nicotine.
Its effect on non-smokers is complex, and definitely not accurately characterized as stress-reducing.