That doesn't answer the question.
We can assume that the cards represent what the Elemental is bringing into battle. That being said, by putting a Poison card in the deck, it is the equivalent of the elemental carry a vessel akin to the one depicted on the card holding a poison. I do not imagine it functioning any different from a smoke grenade, but instead, it actually produces a toxic cloud.
However, this is a different form of poison as is done by any Scorpion, as held by the similar argument of Psion and Lightning. Although they carry out similar effect [both deal spell damage], it does not necessarily mean that they are the same effect, as per your argument. That in mind, we can argue that because of that, even if Poison was a spell, contrary to my beliefs, the reason that its effect is not similar to a SoW [Dune] Scorpion is that it is a different card and, thus, a different effect.
Also, even by your argument, we have found that physical shields still do not block all physical effects. Sure you can argument by my depiction of Poison that it can be blocked with any physical shield. However, there is no defining value to Poison and how it can be blocked. We obviously see that attacks from creatures are physical interactions. However, they are only hindered by shields, not completely blocked.
You argue that the attack can still be done psionically and physically at the same time in order to transfer poison in a same manner. However, you have yet to explain how.
