What you describe is fundamental to advertising. Your specific example was literally a decades long advertising campaign, "I'm not only the Hair Club president, I'm also a client."[1]

I'm not going to buy a pair of shoes just because Michael Jordan wears them. The shoes aren't the reason he was good at basketball and there is no reason to believe this nurse was attractive because of these injections.

[1] - https://www.youtube.com/watch?v=xeFoLdeqG1I&t=55s