I remember Fr. Iscara wasn't too keen on things like this.
I actually saw him throw away a stack of the letter above. Perhaps because it's a textbook example of piety with no basis in doctrine?
It's true, that some people might think that the Faith is a sort of talisman (carry around this letter) and as long as they say a few prayers, they're saved (forget about priests, sacraments, confession, living a virtuous life).
I think that's why Fr. Iscara is angry about things like the above.