I recently played a series against a team which had both of its catchers injured the week before he played me.

As a result he had to use Tony Phillips and Rickey Henderson as catchers that week. They did throw a few runners out. But they also threw a lot of balls into center field (allowing runner from 1st to go to 3rd) and into left field (allowing runner from 2nd to score).

I won two games in that series and both of them were due to several runners scoring on errant throws.

So it does go both ways. In my experience the non-rated catcher cost his team 2 games on defense alone.