I don't know if you are trolling, but.. eh..
Throwing is indeed a secondary skill, it unlocks weapon perks for spears, which do work both in HtH and Throwing, but the chance to hit with those in HtH depends on your HtH% skill.
Same with sneaking.
Throwing is not used here due to several unresolved bugs with spears and other throwing weapons. For an example some spears can't hit from 2-hex distance, they will always miss, no matter your stats or your target's stats are.
Your throwing skill doesn't only increase your damage, but also projectile travel speed, and soon I believe, it will also affect the length of debuffs applied by throwing weapons (spears, stun nades... etc).