Mistress Kim needed to scare the shit out of this guy and that is exactly what she did. She ensured that the guy learned his lesson and that he did things her way. That is why she opted to trample and make him lick her feet. He was scared at what she did to him and he learned to avoid her because he did not want to piss her off.
Mistress Jolie needed to pass a message to her slave and since she did not want to hurt him, she chose to do it with her foot fetish feet. She used her stinky feet to do it in order to warn him about what she could do to him if he messed with her. He learned his lesson and he never pissed her off as she was not going to accept that.