This mistress was bored out of her freaking mind and she wanted to have fun at the expense of this loser so she sat down and thought of what to do to him and she settled on using her soles to dominate him. He had to worship her soles and it was not optional. He had to do it and she made sure of it by threatening to boot crush him if he did not.
Mistress Zora wanted her slave to learn that she was not a pushover and that she could punish and humiliate him in a way he had never been humiliated before. So she used her boots to send a message that if he did not do things her way, he would have himself to blame. She showed him the boots which she was ready to use to torture him if necessary.