When you pitch and your front foot starts towards the target, do you want to lead with your heel to the plate?
You want to lead with what ever is the most comfortable for you while maintaining proper mechanics. Specifically, you don’t want to open the hips too soon so if leading with the heel helps you do that and you are comfortable with leading with the heel, then do so. If you can kead with the toe without opening the hips too soon and that is more comfortable, then do that. There’s no one right way - find what works best for you.