I'll answer why "I" would, and its simple really. Not everyone is the same, so everyone will vape differently. Too me carto's taste like crap, which is why I plan to use RBA's for the foreseeable future. By your mentality in your post, I should be asking you why are you using a carto tank instead of a Z-atty-pro on your "Porsche", but I already know the answer to that