I think that religious affiliation doesn’t matter that much when it comes to voting. In other words, I think he picked up a sizeable minority of Catholics not based on their religion, but because they were union members in traditionally democrat, blue collar districts.
It absolutely does, Jews have NEVER voted republican in our history, Protestants have only voted democrat 3 times (1932,1936,1964) and Catholics have only voted republican five times, (only voting against a dem incumbent once, 1980), and we all know how Evangelicals vote.
It clearly means a lot.