the smell is one reason but i'm not sure is the only reason

Rest assured: The question asks for the "most" often-mentioned reason, so there can be only one. And in our 2013 survey, this was "The Smell".

No it is not the design. We have mad the result public in January (below): the smell has been the most frequent purchase reason. But thanks for your interest, we will use this to make another correct settlement proposal right now. Maybe this time some participants will vote yes, so this can close.