The cheap Russian stuff was and still is lacquered steel cases. They had to do that to prevent rust. And it will coat a gun's chamber when the barrel heats up after a few shots. Most shooters don't clean their guns immediately to remove the lacquer buildup after shooting stops. So the lacquer hardens and becomes almost impossible to remove without a jackhammer. It can be a beeotch to remove after it hardens. In the west we don't use lacquer, we plate the cases with a thin coat of brass or sometimes nickel.

Almost all shot shells are now steel rimmed bases with a coating of brass.

For autoloaders, sure. But most .45 colt firearms are going to be revolvers where it isn't an issue.

Also, even when it comes to autoloaders, "steel" is an umbrella term that encompasses a huge variety of materials. Not all steel is hard enough to damage all firearms.

I don't buy it all the time. But sometimes I do because I just want to feed a cheap gun some cheap ammo.