My face was less than a foot from a 6' long rattler this past fall while filling a spray rig from a 5000 gallon poly water tank. The rattlers around here have evolved to where they seldom rattle when threatened. Some say it is because the feral hogs kill them when they rattle, so the ones that don't are the only survivors. I don't know, but it makes them much harder to avoid. I really don't remember seeing a rattler that announced his presence in the past 5-6 years.
Anyway, he was coiled up against the tank. I would not have been able to safely shoot him with a solid projectile. Those tanks are expensive, and water precious. I have also killed dozens on the porch, on the steps, around buildings, or around trucks and tractors, where I would not be able to chance a shot with solids. Even a few inside the shop.
You're right, in snake country they can turn up anywhere. And, while they can be killed with sticks, shovels, etc., I'm always carrying a gun, so that is handier. And, if you turn around to grab a shovel or hoe, when you turn back, they are often gone. It really sucks to know they are in your shop, or close by, and not know WHERE they are. Puts a crimp in your daily activities.
Carrying a mag of snake shot is wise where they are commonly found.
Having said that, every spring we enjoy gathering rattlers when they emerge from their dens. We carry paper feed sacks to put them in, and snake catchers (pincers) and prowl denning sites. They are so well camouflaged that often, when we see the first one at our feet, when we slowly look around, we will see 20-30 snakes coiled up within 10-15 feet of where we stand. I have caught 40 + snakes per site, and have never had to shoot one in such situations. However, I have been near caves that were so full of snakes that the whole side of the cliff sounded like it was rattling. I am ashamed to say that I didn't have the cajones to go inside. Would have loved to see it, but just not man enough to do so.