Airlines used to allow smoking and had all those issues settled then. Fresher air and not so dry. Lets see if this airline makes $. and be a sucess. We all have said there ought to be choices. This airline is providing one.
Never having been on those flights, I was only speculating - but if things work out then great, I agree, people ought to be able to have a choice.
Having said that, I suspect political correctness would doom such a plan here in the US, despite our high value for 'freedom' and 'choice'.
The more frequently the air is exchanged, the lower the cabin humidity gets. There is almost no moisture in the atmosphere at the cruising altitudes of jets. The moisture comes from inside the plane.
It's not free. The more frequently the air is exchanged the lower the fuel economy. Why should I have to pay a higher ticket price to subsidize someonelse's smoking?