PSA: You don't need assigned seats, but make sure someone pushes people to fill seats
We didn't do assigned seats, and we didn't have bride/groom sides, so people just sat wherever. But if you allow "wherever" to happen, then inevitably, you'll end up with rows of seats in the front/middle just being empty.
Have your venue, friend, or day of wedding coordinator take action and encourage people to move up when sitting at your ceremony. Otherwise you'll end up with many empty seats in the background of your photos like my wedding :')
My wedding was a while ago and it's not a super big deal, but it is a mild frustration because our best wedding photo, with us going down the aisle together, has like more than a dozen empty seats in the background. Just recently went to an event that had someone assertive take charge and push people forward to avoid that and thought "oh, I wish I had this at my wedding!"