Well according to a few studies and some peripheral observations there ARE a few benefits to regularly using tobacco products.
Lower's risk of total knee replacement in men.
Lower's risk of Parkinson's disease.
Lower's risk of obesity.
Lower's risk of unwanted pregnancy..b'cuz you ain't getting any Ashtray-breath.
The Joys of momentary gratification as you feed your habit.
There are suggestions that smoking alleviates ulcerative colitis.
No need to plan for your 80th birthday.
There is some blurriness to this list. For instance, you may not need total knee replacement because you weigh less because of smoking BUT if you DO need total knee replacement as a smoker your chance's of complications are much, much higher.
In just about every other way smoking increases your risk of acquiring or worsening every other disease or medical complication, for instance (and just to name a few):
Coronary Heart Disease
Peripheral vascular disease
Lower respiratory tract infections
Various gum diseases
Premature aging of the skin (your largest organ)
Weaker immune system
Infertility (see benefits #4)
Major diabetes complications
High blood pressure
Decrease in sense of smell
New born complications
An increase of varying degrees of just about every kind of cancer
Increased chance of falling asleep and dying in FIRE. Yes, this has happened.
Increased chance of complications and lengthened recovery periods of many medical procedures and surgeries
...and most significant of all...erectile dysfunction (see benefits #4; again).
And these are just the medical disadvantages to smoking. We won't bother considering the disadvantages related to personal expenses, taxes, social stigmata, or the medical disadvantages of second hand smoke that impacts those YOU ARE CLOSEST TO YOU, or the resale value of that ashtray-on-wheels you call your car or the stench rising from your cloths.