Goddess Nika knew she deserved a raise given how hard she worked. But it was not forthcoming and she knew she had to take matters into her own hands as she had ambitions. She also had dreams and goals. Since she had noticed her boss look at her in a suggestive manner, she used that to her advantage, teased him and brainfucked him with her hypnosis and that is how she got the promotion.
Goddess Saffron did not have anyone to try her hypnosis on. She felt that the best way for her to try it was to do it on someone who did not suspect she had any sinister motive and since she did not have a slave, she used her cousin instead. And she was freaking pleased with how it turned out as she was able to control him and manipulate him.
Princess Serena loves hypnosis because she is able to hide behind it to get what she wants. By the time she is done hypnotizing someone, he or she does not know what happened to him and they cannot point back to her. She was practicing today and she did not want anything from this loser so she hypnotized him as practice but did not do anything else to the guy.