You don't shoot deer behind cover with Buckshot. Buckshot is defeated by the cheesiest body armor they make. Buckshot is fairly easily defeated and is certainly not known for being an excellent penetrator or over penetrator.
I am not saying that Buckshot is bad or wont work on ideal shots at all. I simply say that it doesn't have enough penetration for me. If someone has invaded my home I want to be able to reach them and not let them rest.