Fr Poisson's Marian devotion is not a schtick. It's who he is. He is about as "schtick-like" as the Cure of Ars.
I think what people are missing is that he truly does not have the taint of the world in him. He is completely divested of it. I can't tell you to believe it, but Fr Poisson is one holy priest.
Is that an advantage or disadvantage? Certainly it could be both as long as he is still terrestrial.
He is in a bad place in Kentucky, admitted, and he probably wound up there in his naivete not being aware of better circuмstances. He will welcome and tolerate much suffering, but he is not easily controlled in his devotion, and that will certainly be a rub at some point in Pfeifferville.
I am just praying that he is able to get out of that web. We all should be praying for it. This man deserves it.