Getting guests to let their hair down at an event takes time (and maybe a bit of alcoholic encouragement). A photo booth is a great way to shorten that time (and it won't result in a hangover).
There's something about putting on a silly hat or mask, stepping inside a photo booth, seeing yourself and friends on screen, not quite knowing how to pose for a few seconds and then "flash!", the first photo is taken and everyone is smiling and laughing. The queue begins to form outside the photo booth. Guests begin mingling, showing off their photo strips before hiding them away in their handbags or back pockets. They gather friends and family they haven't seen in ages or don't expect to see for some time, to capture this moment together. They connect, in the photo booth, to create memories that will last long beyond the reason everyone was gathered - the wedding, the birthday, the anniversary, the baby shower, the mitzvah.