There are a lot of reasons why a non smoker might pick up vaping.
I've heard of people picking up vaping 0 nic juice when they are on a diet. Vaping lets them experience all of the wonderful flavors they enjoy, without the worry of extra calories.
My cousins used to hookah, but never smoked analogs. After hearing about how horrible hookah is for you they both picked up vaping, again 0 nic juice.
My wife's friend read an article that stated a small amount of nicotine daily was good for brain health. He went out and picked up a starter kit with 6mg juice from his local shop. He takes 1 puff in the morning and one puff in the evening, and that is it. He, also, never smoked a cigarette in his life.
My boss became obsessed with watching people blow huge clouds on YouTube. He asked if I could help him do what they were doing, in a safe manner. I went out and picked up a mod, atty, couple of bottles of 0 nic juice, battery, charger, and put together a kit for him. Gave him a build that would give him a bit of vapor, but that he wouldn't kill himself with. Lol.
Then there are those that would have picked up smoking anyway. The major benefit vaping offers to them, IMHO, is that (hopefully) they can be persuaded to only use 0 nic juice. The option of engaging in the act, without the nicotine, is something that has never been available before, and is something the anti vaping crusaders, very conveniently, overlook.