Why nobody wants them?

Azzazin - Dreamweaver

I believe asterelle has a nice little online page for evaluating the effectiveness of various shards, if somebody can find the page for it? (I could but too lazy to look lol.)

I tell everybody to get jades, yeah. Only seekers and barbs debuff defense levels, and even then not much, so quite reliable in terms of reducing all incoming damage. And versus +10 vitality stones, well, my argument for that is thus: even if it was the SAME survivability, jades are better... because its easier to heal a person with low hp high defenses than a person with high hp low defenses, whether that healing is hp pots or a cleric. In some cases hp works against you, say, in AEU with the boss knocking off 50% of your hp every few seconds.

And to those people who'd advocate dots, I say, nonsense. Maybe you don't hit quite as hard, thats a fact, BUT your survivability which is vastly greater than DoT counterpart, means you get way more opportunities to attack, or you can attack and ignore your enemy's own attack, where a DoT build would need to flee.