What ever good was ever intended by it?
It was created to exclude James III and VIII. The irony is that the entire line that was grafted in failed. Then they had to scuttle around and put Germans on the throne rather than their Catholic englishmen.
My guess is, stability as opposed to the country going back and forth with each royal generation. But I am trying to be charitable here, as the Church of England stood for something meaningful back in the day.