Does anyone actually use them? So far, they all seem like a complete waste of time.

Poison does less damage than a Scourge/Banish over it's full duration.
Slow doesn't make a noticeable difference in the enemy's attack speed, if it does anything at all.
Bio II and Dia II suffer from the same problem as Poison; less damage than a Scourge or Banish. With Bio up, I don't see any reduction in the damage monsters hit me for.
Absorb ATK/DEF/EVA/ACC don't seem to do anything. I don't see any increase in enemy misses or any reduction in the damage they hit me for.
Paralyze doesn't do anything. If the monster's attack is paralyzed, it just attempts to do it again instantly.
Blind doesn't give me any noticeable difference in the target's accuracy.

Basically, Silence is the only debuff that actually seems to work. Am I missing something here?