Kenobi wins sabers because he's honestly a considerably more impressive duelist. His defeat of Grievous, performances against Maul, mustafar Anakin, etc. are considerably more impressive than defeating Darth Nihl, and I really just don't view Cade as comparable to Krayt in lightsaber combat as most people do.
Cade seems to have more raw telekinetic power, as well as more versatility with his abilities.
Kenobi's dueling edge just seems much more impactful here to me.