Are Poison Aura Summons Worth It?

[PyroStock]

I know these summons can work as with enough gems near anything can work, but at the risk of upsetting the bogbeast dieties are summons with poison auras ever worth it?

If they required fire gems (which wouldn't be in theme) I might be able justify the cost easier. They seem to all have map move 1 and are slow in battle which doesn't help. Their attack and defense skills range from below average to puke awful. Catoplebas at least has a death stare, but is that enough to justify the cost? Perhaps one could create a large poison aura army for stacking the poison auras, but that's a lot of gems it wouldn't be very easy to combine with traditional armies later. The Bladder Stick(s), Foul Vapors, and/or Poison Cloud seem a lot cheaper and better if you want to go the poison cloud route.

Are there specific nations (regenerating giants or Ermor's undead or Pythium's hydras or?) where you have used these units regularly and found them worth the cost... or are they more of a "can be fun" unit?