>If you scratch or chip the paint steel will corrode
this isn't really true.
yes, exposed steel will show rust, but that's not what "corrodes" iron to the point of weakness. to corrode in a way that weakens iron, it needs to be kept wet over an extended period of time. If you've seen an old car with holes rusted through, that has occurred "from the inside" in places where water can collect and sit. The outside of objects will dry after rain, and such corrosion will never be a problem beyond aesthetics.
this isn't really true.
yes, exposed steel will show rust, but that's not what "corrodes" iron to the point of weakness. to corrode in a way that weakens iron, it needs to be kept wet over an extended period of time. If you've seen an old car with holes rusted through, that has occurred "from the inside" in places where water can collect and sit. The outside of objects will dry after rain, and such corrosion will never be a problem beyond aesthetics.