Although I find armor and weapons with no Life Line yet having hit point bonuses. So if I understand you, Life Line is the only hit point enchantment. Point 2, enchanting 4 pieces of armor with the max Life Line would yield, 108 HP and cost 4 Malachite gems, the rarest gems in the game.
I wouldn't want to trust my "life Line" against a critical hit. I have been hit with over 200 damage even in the early game. Yes I died, reloaded, and no the current Life Line of 9 HP did not protect me.
Conclusion: Life Line is lame; it is so not worth it on numerous levels!!! I'll take my chances finding random HP bonus equipment that offer 60+ HP and increase my Vitality.
