That's because it's tiny. The box is about the same size as a Cyberverse Commader. Exclusives are primarily done because retailers don't have the space in Japan for repaints and remolds. However, on tiny figures like these, they can have more in stock with the same amout of space. Plus, KTs are priced to move unlike Figuarts.

PS except for the Denliner playset, KT exclusives are pretty cheap too.

And they tend to be either repaints or minor remolds. Again, except the Denliner.