I feel like in a few cases it could be valid evidence, if somebody had a very distinctive “bite profile”. My bottom teeth got crowded after I had my braces taken off when I was teenager, so one of my teeth is off by a good amount compared to the rest. When I bite into something it does leave a distinctive bite mark that I’m pretty sure a good amount of the population probably doesn’t have. It obviously doesn’t translate across the board to everyone else with your goddamned perfect, straight teeth, and it’s not slam-dunk evidence, but it could help narrow the pool of suspects I should think in at least some cases.