Are there situations where Stamina or Magicka Damage is really useful?
You're right, the Damage Magicka and Damage Stamina enchantments aren't terribly efficient.
Absorb Magicka and Stamina have their place, but in general, you'll find opponents regen Magicka to fast for Magicka damage to be terribly useful - generally, by the time you've done enough for it to be really effective, you've hit them enough times to kill them anyway. Stamina is a bit more useful - an opponent with low Stamina will have trouble blocking and power attacking, which can shorten a protracted battle, but given the magnitude and base uses of the enchant, you're often much better off using an Frost Damage or Absorb Stamina enchant - you'll find them to be much more effective overall.