There's the risk that ecigs are an on ramp to actual cigarette smoking. That reflects my experience, first using a friends vape now and then to bumming the occasional cigarette to actual smoking. There's a symmetry we don't like to acknowledge between what makes vapes good for quitting - you can slowly ramp your nicotine - and what makes vapes good for starting. See this study: https://jamanetwork.com/journals/jamapediatrics/article-abst...