This can only be our fantasy.There is no official information on what these skills affect. You can't visually see what the player is hitting during a corner kick, the animation is the same as for a regular kick.
But I still think the heading is secondary for the striker. DC play with their heads both in defense and in attack, and ST only at the moment of corner kicks.
And as far as I understand, the 1 on 1 game is affected by the finishing. Creativity too?