When goddess Harley realized that this guy was a pervert, she knew she had to punish him. And that is why she felt that the best thing to do to him was to financially punish him and at the same time get him to change his behavior. The financial part was to benefit her and the other one to benefit the guy so that he stopped his perverted tendencies. It worked.
Goddess Harley loves to spoil herself especially on crucial and important days such as her birthday. The mistress used her findom pov fetish to dominate this guy financially and she used the money she got from him to spoil herself. She is extravagant when it comes to things like birthdays and hers had to be the best. So the guy definitely felt a dent in his pocket as a result.