Interesting...I do drink in front of him (big fan of craft brews, especially IPA's), and he knows it's beer, and I've also explained to him that it is for grown-ups only. Granted, I'm not pounding a 12 pack and getting wasted, but I don't see any issue with daddy have a glass of beer with dinner.
As a small example - my brother drinks beer. Usually just one or two at a time. I am sure their child knows that its for grown ups, but he at his young age has come to regard beer in an entirely positive light - a sort of mental medicine for stress or unhappiness - for adults, basically as a "treat". I am not even sure my brother is aware of this, or that he would regard it as any issue.
This doesn't accurately represent the nature of beer, that it is an unnessasary habit, and not a health food, or medicine, or equivilant to putting your feet up, or having a hot bath. While in moderation its not terribly unhealthy, it is a drug.
To some degree such normativeness is unavoidable, because its how many veiw alcohol, being the most popular drug in western civilisation, but all the same, this normativeness will incline imitative behaviour in later life.
Vaping is mildly habituating (much less than smoking), and mildly unhealthy (approximately as bad as a full on coffee habit).
Are you sure your veiwing these two habits objectively? maybe you have carry over guilt from the social stigma of smoking?
I would personally just give a little explaination of both of these habits.
"This is called vaping. Vaping is something some adults, former smokers, do to replace their smoking, and to relax, because its not nearly as bad for you as smoking - but people who don't vape or smoke do better at relaxing without it.
And vaping is a bit addictive (ie hard to stop once you start) so your better off not ever trying it, even as an grown up. Life is better without it, its just something I do, because I used to smoke, thats even harder to stop, and I don't want to smoke anymore"
"Beer is something some adults drink to relax, or as a treat, but grown ups who don't drink beer relax well and enjoy themselves just fine without it too"
"Both these things aren't very bad for you, but aren't good for you either. They are definately for adults only"
Something like that....(very roughly). Just so the objective veiw is had, for when the child makes their own decisions later in life.
They would then know well enough, not to worry for you (unduely, seeing as these are both low harm activities), but also to take their own choices with some wisdom and gravity when its their turn.