wondering what exactly this does. does it help in protection or other things? i guess i am wondering if it is better to enchant with fortify light armor or fortify health? thanks

it makes your light armor more effective, so yeah 25% increase gives you more armor protection, it makes the light armor you're wearing better.

It increases you light armor skill.

Depends on how good the armour is. If you are in smithed up dragonscale, and near the cap, go with fortify health. Also fortify health is of benefit against magic, armour alone isn't.

Fortify armor skill is almost completely worthless.

I used it for my follower because I dont think they get perks.