Although...
There is a crowd that says that brass, plastic-coated or aluminum rods can pick up bits of fouling and dirt; then scratching the bore as the rod is shoved thru.
Steel rods won't pick up that kind of debris, since it is harder.
Myself, I still use brass, Al, steel, and plastic-coated rods.
I just make sure there isn't all kinds of grit around the benchtop, and I wipe the rod with a cloth after each pass through the bore.
Well, actually, I only adhere to this with my Anschutz Exemplar, my AR, some finer .22 revolvers, and my Dad's 722 in .222Rem.
Guns that are that accurate need a nice bore.
It is my opinion that the combat accuracy of a 3" .38 Special will not be adversely affected by a few small scratches in the bore.
Nicks on the crown however, can throw bullets wild.
$.02, -Kframe