Don't know if this will muddle it up more, but maybe look at it this way: Balloon Lizard has an effect that triggers in the Standby Phase. This means that at some point during the Standby Phase you have to go: Lookie here! I am using Balloon Lizard's effect! Yay! Divine Wrath me!
Skilled Dark Magician on the other hand has to wait for a Spell Card to resolve. It waits for the Pot of Greed to be activated and it looks and says: Ok, I'm getting ready... ... gonna do it ... gonna do it ... nah, I'll just wait a bit. Probably not going to get to resolve anyways (SDM has some self-esteem issues). Pot of Greed finally resolves, and it, being the nice pot with the really scary smile that it is, says 'Here, take this. I'm on my way out right now, but you could probably use it.'
(Ok, this is why it is bad for me to answer questions when I'm supposed to be writing a paper. . . )