Here's another way to judge the benefits. n=1 I switched to
vaping 5 years ago, age 65, after smoking 40 of the previous 50 years. Then I learn from a check up, I didn't get healthy, just less unhealthy. So I reformed diet and exercise, reduced body fat about 30 pounds to 13%, added may be 10 lbs of muscle, I eat low carb, real food, +40% of daily calories burned by exercise, normalized blood pressure, blood fat and blood sugar. Lung exam and xray normal. All that took effort, there are no garrantees, and none of it possible without stopping smoking first. The war on vaping is truely disgusting and an existential threat to my new found health.