Chewing tobacco would also contain the carcinogens of tobacco resting in your mouth, causing cancer generally wherever it sits. The tobacco is still the delivery system for the nicotine. In the case of some snus, some are tobacco free, and are simply nicotine pouches that have soaked flavor and nicotine into them. Nicotine, like caffeine, vanillin, THC, can be extracted into its pure form from tobacco, removed from tobacco entirely and delivered in safer methods. This is the mindset behind vaping.