[…] The theory is that the more attractive people working such jobs, the weaker the economy, while in reverse the fewer attractive people working such jobs means a stronger economy.This assumes that attractive people have less trouble finding better work opportunities during good economic times, while during poorer economic times such higher-paying jobs are more difficult to find, therefore more attractive people will be working as waiters.
[What is hot waitress economic index? definition and meaning]

Je n’ai pas trouvé d’article vraiment sérieux sur le sujet, mais c’est à creuser. Et au delà de l’esthétisme, c’est globalement le CV, humain et professionnel, qui est à prendre en compte.