Why are vapes more commonly used than cigarettes?

Two and only two reasons:

1. Because of “coolness”. Whether because they personally see it as cool, or because of peer pressure (everybody is doing it) it boils down to the perception that it looks good.
2. For the nicotine. It usually is to help quit smoking, by taking the craving for nicotine out of the many things that make quitting smoking difficult. (It also helps with the problem of what to do with your hands and mouth that used to be occupied by the act of smoking.)

Despite arguments on whether nicotine is addictive, habituating, or no worse than caffeine, it does have some desirable effects. It can be calming under stress; it can help with concentration; it may have some positive effects with largely mysterious ailments like Alzheimer’s and Parkinson’s.

I used vaping to quit smoking. Despite the poor quality and effectiveness of early e-cigs, I managed to quit from a VERY heavy smoking habit (as much as 4 packs per day of unfiltered cigarettes), and I was able to do it overnight: my last cigarette before going to bed; began vaping in the morning; never needed another smoke.

I suppose I could have gradually lowered the nicotine content of my e-cigs – eventually to zero – and then weaned myself from using e-cigs altogether. However, I like the effects of nicotine and plan to continue vaping with nicotine. I accept that there are some negative effects of using nicotine, but I feel that the positive effects (including such nebulous concepts as “enjoyment of life”) outweigh the negative ones.

There are also costs to vaping which are unrelated to health: money (although less than a tenth of the dollar amounts required for smoking); pressure from politicians and society in general (we can hope that this will be eased by education); the simple mechanics of vaping (keeping a supply of e-juice, maintaining equipment, carrying it around, etc.). I think these are all acceptable costs as well.