What a strange ad campaign

There is a hair transplant company around here that has a weird billboard campaign. Each of their billboards have two men on them, one bald and one with hair. And it's not a before and after thing. They are different men. So if you run a hair transplant company, why would you put a bald man on your sign? That seems like poor advertising. And it's obviously their plan since they have two different sets of billboards that I have seen. One set has old men and one set has younger men, but both sets have two men, one of whom doesn't have hair. Why would they do that?