because it's not like you drove up to, like. Barrie, Ontario and now you have five hours to fill and there is nooooothing to do.
My friend did a destination wedding years ago and there might have been that long a gap between ceremony and reception. It was enough time that we did pictures, and then me and the other bridesmaid got drunk on pina coladas with her parents, helped them get back to their room, and then went to our room, showered, had a snack and watched a movie before going to the reception on the beach -- it was definitely dark by then. Probably more like four hours, but in that scenario, it's fine. In others, it would be a pain.