Snakes have their place in nature, but most people do not want them in their yard. As a former vet tech we worked on many snakes inserting transmitters under their skin for a research project sponsored by the government. We did mostly black snakes and corn snakes, we also did about 5 copperheads, 2 rattlesnakes and a cottonmouth. It made me a little nervous with the poisonous ones but it was very fascinating.
Being in a rural practice we also treated many dogs for snake bites. It was mostly supportive care and about 90% pulled through.
I still would not want any in my yard.