Attending that open house gives u more points to get invited to the actual interview?
Attending the open house has got nothing to do with scoring points, it's about getting an idea of what working for Emirates is like and assisting you in making a more balanced decision on weather you want to apply or not.
Is it better to bring your wife with you
Your wife is going to be the one stuck in Dubai while you jet around the globe. Yes its better to bring her to the open day she can also form an opinion. Encourage her to ask questions and then should you get called for an interview in Dubai, make bringing her with a priority.