I'm not 100% pro-legalization, but the main argument there is that the laws on the books are draconian and variably enforced. We probably don't want that for consuming anything relatively harmless, like vaping or weed.

I think the jury is out on how addictive any of these substances can be, and since the legal age for smoking is 18 there's a significant worry that vaping is affecting the health of our kids (almost definitely true). The same is possibly true for marijuana, it's just less well studied (and these health studies are new).