Yesterday while training, a mom asked what the importance of the front foot was. My response "get in your way".
When the front foot hits the ground your momentum will stop. If you are still moving forward while this happens your body will have to go up and over your hip causing you to rise up as you swing. It looks like a golfer. You see this heavily in pitchers that do not us their legs when they throw. The will almost always miss high.
But the mom's question was more directed at the direction of the toes at strike.
The hips are the strongest part of your body. They will always win. If your foot strikes with the toes pointed at the plate your hips will force your foot to roll over and your momentum directed towards third base. Also your hips will only be allows to rotate 3/4 of the way around causing loss of power. If the toes are pointed more to first base or the pitcher then the hips get full rotation and your are balanced at contact and ready to run to first.
Know the Why