Wearing a suit is just a traditional way of signifying that you see yourself as above the class of people that have to use their physical body in some way to make a living. It also shows that you've committed yourself to not doing anything playful and fun outdoors for the day.

Wearing a well fitting suit might get you a lot of attention from women, but its going to be a certain demographic of women that value money and status over other things that may or may not be more important to you.