In GTA V you can hold the preform action button to smoke a cigarette for longer and take a few good hits. In a car, you can smoke the same cigarette infinitely
In Red Dead Redemption 2 Arthur only takes one drag off cigarettes and even cigars before snuffing out
At worst, smoking may not even be in GTA VI. A core game play feature of 5 reduced down to nothing
smoking helped me not get blasted by moving trip mines so it seems overall pretty positive for my health