Mistress Kira loves to punish especially when she stands to benefit directly and that is why she chose to use her sneakers to ballbust and humiliate this loser. The mistress wanted to shock the guy with her cruel act and when she was done with it, she wanted to make the guy fear her and do whatever she wanted. It worked that way as she achieved what she had wanted.
Mistress Kira had tried to tolerate her slave but she could not and she had to make sure he changed. So she waited for him to make another mistake for her to choke him with her sneakers. And once he had made the mistake, she did not wait for him to do anything else. She removed her sneakers and she used them to punish him as he struggled to get himself free but could not because she was surprisingly stronger than him.
When this mistress decided to dominate this loser, she knew the best way to do it was to do something he had never experienced before. That is why the mistress cruelly used her smelly sneakers to dominate him and he learned his lesson. It was both painful and it was humiliating as he had to endure being trampled with the sneakers and also licking them and especially the soles of the sneakers.