Why does Karate recommend kicking with feet instead of shins?

Question

What is the historical reason Karate and Taekwondo recommend kicking with foot instead of shins for Round kicks (different from Muay Thai)?

In Krav Maga, they teach to kick with foot, since most of the Israeli soldiers are wearing sturdy thick army boots, and the small bones will not break, while giving longer kicking range. Is there a reason, Karate and TKD recommend this? Maybe warriors wear metal samarai boots during ancient times?

I see many young adults especially in TKD learning, and last thing people want are kids having injury in self defense.

Note: Prefer post not be about which martial art is better, and more professional about understanding the historical context.

Answer 1

Karate doesn't limit its kicks to either foot or shin. Some forms of karate - such as sport-oriented styles - might emphasise feet as a means of maximising reach, but most full-contact and traditional schools train to employ the shin, top of ankle, instep, heel, both sides of the foot, ball of foot and toes.