If there's one thing I think is absolutely true in the world of addiction, its that people will find an addiction. Everyone has a way to trigger a dopamine release; most of the time its multiple ways. Eating fatty/carby food; soda; caffeine; alcohol; smoking; vaping; marijuana; porn; masturbating; sex; exercising; prescription medication abuse; cocaine; video games; physically abusing other people; all of these tie back to releasing pleasurable chemicals in the brain of someone, and that's why they do it. Addiction is a foundational constant in the human experience.
Point being, you can't get rid of addiction without getting rid of pleasure. Which means, you can't get rid of addiction. So if you tell kids "don't smoke, don't vape, don't do anything, its all bad because its addicting", you're basically self-selecting what addictions our culture has labeled as "fine" without understanding all of the side-effects of the addiction. Heart disease kills more people than cigarettes and alcohol ever did; are we ready to say you have to be 21 before you can buy McDonalds?
What I'm trying to arrive at is this: I'm all for the development of safer, more accessible dopamine delivery systems. One way to look at them is that they're a gateway to harder stuff, but I tend to disagree. They will be that for some people, but those people were lost to begin with. They would have found cigarettes whether they had help from vaping or not.
I think if you accept that addiction is a constant and everyone needs an addiction, then they can actually be a net positive because they can help people avoid the harder stuff. If the only way you have to trigger your dopamine is cigarettes, then if you're not doing cigarettes you're doing alcohol, cocaine, fatty foods, porn, etc. And, really, we need more research on vaping, but from the scientific research and statistics we have: vaping might be "healthier" than all of those.
Its not healthier than doing nothing, but doing nothing isn't an option.