Typically if you go into the Emergency Room with a snake bite, the first question asked is "did you kill the snake and bring it with you". A quick, positive ID of the snake species will have a profound impact on the treatment used. Certain types of venom require specific antivenom. Yes you could measure the two puncture wounds, distance apart, diameter, and compare it to a snakebite directory, but that takes time. This may not be as important in some regions as there may only be one species of venomous snake, but here in the Southwest, you have a handfull of dangerous snakes and that ID time is critical.