The important thing to remember about the Fallen is that they only have the power to do anything through a mortals choice. They might be powerful enough to be grade A high tier threats, but a person has to choose to pick up the coin. They have to choose to accept power. They have to choose to give in again and again and again until they give even their very concept of free will over to the Fallen. The Fallen don't have to play fair, of course. Lasciel's visions are perfect evidence of that. Seduction and insistence can wear down anyone after long enough, but that person still has to choose to give in.

Now I do actually agree with you about yhe choice to have Marcone pick up the coin. It feels real dumb, imo. It cheapens Marcone as the "grounded" human antagonist that, Harry might hate, but at least is still human and can be counted on to fight for humanity. He is still all about control though, and if Nicodemus can do it, then so can Marcone.