The infuriating thing for me is I am almost certain that the technology and general idea behind it make sense. It should be possible to build a machine that turns a non-toxic substance into a vapour that can deliver a hit to the throat/lungs like smoke but that is composed of non-harmful substances. That must be possible and can't be that hard! We can put a man on the moon, for chrissakes we must be able to create water vapour!
My fear is not so much about the theory, it is that the actual units themselves (or the carts/liquids) contaminate the vapour, for example through liquid reacting with the plastic containers, or the atomiser metal degrading into the vapour. Stuff like that is really scary to me. A well-built, non-leaky vapouriser would, I believe, have a really good chance of being totally safe but I'm not 100% sure that's what we are using.