Wouldn't have a hat/fascinator for a start.
Sometimes if you are going to be out for a long day / standing around for photos for an hour or so / sitting in what may well be a cold church, you need to think more practically in terms of having a jacket that is part of the outfit, etc., but for an evening, you only need the 'indoor, going to a party' bit which might be the dress on it's own, for example.