While Keyword Difficulty is a handy metric to have, it only shows the ease of ranking in the Top 10.
This seems to be a hang-up of old school SEO. Surely in 2018 and beyond we want to go beyond just appearing on the first page of the SERPs?
Traffic is negligible in the lower positions, so I'd be much more interested in a Top 5 or Top 3 KD score. If the UI / UX permits, all three would be great (Top 3, 5 and 10).