Because its arguably worse than smoking cigarettes overall.
The health effects aren’t researched enough for a proper comparison between the two, but at least short term studies, while being inconclusive, show that vaping is just as damaging as smoking. The glycerine based liquid can damage your lungs more than smoking would. And while cigarettes have a lot more different carcinogens, what matters more is the amount.
In addition to that, vapes taste a lot better than cigarettes, which removes the first hurdle that smoking usually has. And this isn’t only relevant when talking about children, its the exact same thing for adults. Most smokers I know startet smoking more when they switched to vapes.
Then there is the whole issue with one time vapes and batteries in landfills
If the state of the Scottish energy grid is comparable to mainland Europe, then the prices go up due to increasing cost of infrastructure.
Renewables are a lot cheaper per kWh, but require a substantialy higher up front cost in infrastructure due to their decentralized nature.
Before renewables, the electricity only ever flowed in one direction, from the power plant down to the consumers. A few centralised main powerlines could deliver most of that.
With the increase in renewables that suddenly isn’t true anymore. Smal villages often are net positive, we’ve reached a point where even the medium voltage grid of entire regions is net positiv and the energy has to be transported somewhere else, sometimes even outside the country.
All this requires substantially more powerlines (or at least thicker ones, so still new cables). But more importantly, devices to measure the current load of the grid at all times and modernized equipment that can remotely be operated to respond to variing load.
Not to say that we should stop building renewables. All this infrastructure will be needed eventually eather way, but at least in the short term, investments will be needed regardless.