Quote Originally Posted by RyuDragnier View Post
There's actually a logical reason behind this. The poison the NIN apply to their daggers are from various poisonous creatures, whose venom melts through all manner of things. The various SMN/SCH DoTs work because they're corrupting aether, something all matter has in Eorzea. But you cannot inject actual poison into something non-living, nor can you Disembowel something non-living. This is why neither of those two abilities work on things such as the boulders in Copperbell HM.
Except, this doesn't actually work. Summoner spells description alone breaks your logic by the simple quote. "Causes fever and lungs are failing." Rocks, Totems, and Dragon heads (In WoD on the 2nd boss are immune to Venomous bite too.) do not have lungs or white-blood cells. And even then, it's still the same concept. It's both poisons. If we got by that same logic, bard should be nearly worthless against these objects alone. How effective exactly is an arrow against a rock? Chances are, it won't pierce. It's more likely to ricochet.