A. The Catholic Church is what she says she is [i.e. infallible], or
B. The Catholic Church is fallible, and therefore NOT what she says she is
So, either way, I’m better off being Catholic — it is epistemically preferable to choose to be Catholic — maybe not morally if she is not what she claims to be — but epistemically, it would. Analogy: If I could hire a tour guide and have a map, or just have a map, it would be epistemically preferable to have the tour guide also, if only as a possibility the tour guide new what the heck they were doing. In other words, all I need you to do is grant “A” is possible to make following the Catholic Church epistemically preferable. Given your inquiry into the Catholic Church, do you find A to be impossible?
Me: There are a few problems, as I see it, with this line of reasoning. Both camps, Rome and Protestant, agree that Scripture, as given in the original tongues, is the infallible word of God. Rome, though, claims the Pope is the sole infallible interpreter of all doctrine in Scripture and teaching of the Church. In other words, by definition, whatever Rome teaches is correct and without error whether implicitly or explicitly taught in Scripture or not.