Why stop at smoking?
We can charge people for health insurance based on how healthily they eat, whether they consistently wear sunscreen, how much exercize they get, how dangerous their hobbies or habits are (motorcycle? skydiving? oh boy), etc etc.
In fact, health insurance in USA DID do things like that before the 2010 ACA -- but limited by incomplete information. With smartphone surveillance (hey, why not require smartphone surveillance to get a certain product), the amount of factors you could monitor and charge based on go up a lot.
Except the ACA prohibited this... EXCEPT for smoking, in fact. "I wish people who smoke could be charged more" for health insurance -- in fact, they CAN. It's about the only thing the ACA allows differential pricing on.
Why is smoking different to you, or to the policy-makers who decided on that in the ACA? I don't really get it.