At a cost of 2 AP and creating a very small ring of smoke around you for a single turn, I'm just not seeing the point of it at all.
It even breaks stealth when you cast it.
In theory, it should hide you from enemy attacks for a turn, as an alternative to stealth. In a lot of other games, you could also attack from within it in, but you can't here. Magically though, enemies can hide in smoke all day, and you cannot target them, but they can shoot you just fine.
