Stainless steel mag springs are very popular with SASS shooters. Moving guns from the house to the car an onto the range brings condensation that works its stuff inside the mag tube. Magazine tubes are catching on no matter if some say it does not look "proper" to them.
I must admit I don't like the SS mag tube look either. I keep my 1873s wiped and oiled inside and out.
The Marlin lever action benefits from a clean tube/follower because the operating cycle depends on the round being soundly pushed onto the elevator/lifter.