most e cigarettes contain only water and flavoring Vaping Flavoring Agents in E-cigarette Liquids:

As a result of the rules put in place by the TPD, vape products including disposables are only available in certain strengths and volumes in the UK

Articles were excluded if they: (1) reported litter and cigarette butt densities using the items per meter unit, (2) lacked numerical data on cigarette butt density or the specific percentage among anthropogenic litter, (3) focused solely on public perception or smoking behavior, and (4) were conducted exclusively indoors or in controlled laboratory settings

As for smoking, the taste is the same as the aroma just cigarette tobacco

Its not necessary, and it can wear out the battery over time

Compared to Rich Regular, it has a miscellaneous taste, but it also has a tar-like taste