If Y is a strenuous activity (walking when very overweight), if the problems caused by X (obesity) are mostly long-term, and if Z is a device that offers immedi

If Y is a strenuous activity (walking when very overweight), if the problems caused by X (obesity) are mostly long-term, and if Z is a device that offers immediate relief for X's short-term problems, then yes people very often buy Z. People choose immediate gratification over long-term solutions all the time.