Reason #2 - Time! As a photographer, the First Look makes my day! Why? Well, after the couple finish their moment we will go out and do all the formal shots of the couple, then gather the wedding party for some fun wedding party images, and then usually finish all the posed family shots - ALL BEFORE THE CEREMONY!!
Why is this so amazing? Well, you can enjoy your ceremony and then move right into your party without having your guest wait around for hours while you take photos! Its a win-win for me, the couple, and the guests!
However...I do usually like to take the newly married couple aside for a few more shots together because now they will have that freshly married glow!