Not at all. If you tilt the gun so the sight is vertical, yes, obviously; but if you simply aim over the angled iron sights, you're totally in business. We're not talking about trying to get good groupings, we're talking about hitting man sized targets at ranges where a magnified sight is a hindrance, ie right in front of you, ffs!
Doesn't matter, you cab still use these holding the gun normally so shouldn't have any adverse effect- though assuming the user is right handed, they would be better off on the other side of the rilfe